diff --git a/.idea/uiDesigner.xml b/.idea/uiDesigner.xml
new file mode 100644
index 0000000..2b63946
--- /dev/null
+++ b/.idea/uiDesigner.xml
@@ -0,0 +1,124 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="Palette2">
+    <group name="Swing">
+      <item class="com.intellij.uiDesigner.HSpacer" tooltip-text="Horizontal Spacer" icon="/com/intellij/uiDesigner/icons/hspacer.svg" removable="false" auto-create-binding="false" can-attach-label="false">
+        <default-constraints vsize-policy="1" hsize-policy="6" anchor="0" fill="1" />
+      </item>
+      <item class="com.intellij.uiDesigner.VSpacer" tooltip-text="Vertical Spacer" icon="/com/intellij/uiDesigner/icons/vspacer.svg" removable="false" auto-create-binding="false" can-attach-label="false">
+        <default-constraints vsize-policy="6" hsize-policy="1" anchor="0" fill="2" />
+      </item>
+      <item class="javax.swing.JPanel" icon="/com/intellij/uiDesigner/icons/panel.svg" removable="false" auto-create-binding="false" can-attach-label="false">
+        <default-constraints vsize-policy="3" hsize-policy="3" anchor="0" fill="3" />
+      </item>
+      <item class="javax.swing.JScrollPane" icon="/com/intellij/uiDesigner/icons/scrollPane.svg" removable="false" auto-create-binding="false" can-attach-label="true">
+        <default-constraints vsize-policy="7" hsize-policy="7" anchor="0" fill="3" />
+      </item>
+      <item class="javax.swing.JButton" icon="/com/intellij/uiDesigner/icons/button.svg" removable="false" auto-create-binding="true" can-attach-label="false">
+        <default-constraints vsize-policy="0" hsize-policy="3" anchor="0" fill="1" />
+        <initial-values>
+          <property name="text" value="Button" />
+        </initial-values>
+      </item>
+      <item class="javax.swing.JRadioButton" icon="/com/intellij/uiDesigner/icons/radioButton.svg" removable="false" auto-create-binding="true" can-attach-label="false">
+        <default-constraints vsize-policy="0" hsize-policy="3" anchor="8" fill="0" />
+        <initial-values>
+          <property name="text" value="RadioButton" />
+        </initial-values>
+      </item>
+      <item class="javax.swing.JCheckBox" icon="/com/intellij/uiDesigner/icons/checkBox.svg" removable="false" auto-create-binding="true" can-attach-label="false">
+        <default-constraints vsize-policy="0" hsize-policy="3" anchor="8" fill="0" />
+        <initial-values>
+          <property name="text" value="CheckBox" />
+        </initial-values>
+      </item>
+      <item class="javax.swing.JLabel" icon="/com/intellij/uiDesigner/icons/label.svg" removable="false" auto-create-binding="false" can-attach-label="false">
+        <default-constraints vsize-policy="0" hsize-policy="0" anchor="8" fill="0" />
+        <initial-values>
+          <property name="text" value="Label" />
+        </initial-values>
+      </item>
+      <item class="javax.swing.JTextField" icon="/com/intellij/uiDesigner/icons/textField.svg" removable="false" auto-create-binding="true" can-attach-label="true">
+        <default-constraints vsize-policy="0" hsize-policy="6" anchor="8" fill="1">
+          <preferred-size width="150" height="-1" />
+        </default-constraints>
+      </item>
+      <item class="javax.swing.JPasswordField" icon="/com/intellij/uiDesigner/icons/passwordField.svg" removable="false" auto-create-binding="true" can-attach-label="true">
+        <default-constraints vsize-policy="0" hsize-policy="6" anchor="8" fill="1">
+          <preferred-size width="150" height="-1" />
+        </default-constraints>
+      </item>
+      <item class="javax.swing.JFormattedTextField" icon="/com/intellij/uiDesigner/icons/formattedTextField.svg" removable="false" auto-create-binding="true" can-attach-label="true">
+        <default-constraints vsize-policy="0" hsize-policy="6" anchor="8" fill="1">
+          <preferred-size width="150" height="-1" />
+        </default-constraints>
+      </item>
+      <item class="javax.swing.JTextArea" icon="/com/intellij/uiDesigner/icons/textArea.svg" removable="false" auto-create-binding="true" can-attach-label="true">
+        <default-constraints vsize-policy="6" hsize-policy="6" anchor="0" fill="3">
+          <preferred-size width="150" height="50" />
+        </default-constraints>
+      </item>
+      <item class="javax.swing.JTextPane" icon="/com/intellij/uiDesigner/icons/textPane.svg" removable="false" auto-create-binding="true" can-attach-label="true">
+        <default-constraints vsize-policy="6" hsize-policy="6" anchor="0" fill="3">
+          <preferred-size width="150" height="50" />
+        </default-constraints>
+      </item>
+      <item class="javax.swing.JEditorPane" icon="/com/intellij/uiDesigner/icons/editorPane.svg" removable="false" auto-create-binding="true" can-attach-label="true">
+        <default-constraints vsize-policy="6" hsize-policy="6" anchor="0" fill="3">
+          <preferred-size width="150" height="50" />
+        </default-constraints>
+      </item>
+      <item class="javax.swing.JComboBox" icon="/com/intellij/uiDesigner/icons/comboBox.svg" removable="false" auto-create-binding="true" can-attach-label="true">
+        <default-constraints vsize-policy="0" hsize-policy="2" anchor="8" fill="1" />
+      </item>
+      <item class="javax.swing.JTable" icon="/com/intellij/uiDesigner/icons/table.svg" removable="false" auto-create-binding="true" can-attach-label="false">
+        <default-constraints vsize-policy="6" hsize-policy="6" anchor="0" fill="3">
+          <preferred-size width="150" height="50" />
+        </default-constraints>
+      </item>
+      <item class="javax.swing.JList" icon="/com/intellij/uiDesigner/icons/list.svg" removable="false" auto-create-binding="true" can-attach-label="false">
+        <default-constraints vsize-policy="6" hsize-policy="2" anchor="0" fill="3">
+          <preferred-size width="150" height="50" />
+        </default-constraints>
+      </item>
+      <item class="javax.swing.JTree" icon="/com/intellij/uiDesigner/icons/tree.svg" removable="false" auto-create-binding="true" can-attach-label="false">
+        <default-constraints vsize-policy="6" hsize-policy="6" anchor="0" fill="3">
+          <preferred-size width="150" height="50" />
+        </default-constraints>
+      </item>
+      <item class="javax.swing.JTabbedPane" icon="/com/intellij/uiDesigner/icons/tabbedPane.svg" removable="false" auto-create-binding="true" can-attach-label="false">
+        <default-constraints vsize-policy="3" hsize-policy="3" anchor="0" fill="3">
+          <preferred-size width="200" height="200" />
+        </default-constraints>
+      </item>
+      <item class="javax.swing.JSplitPane" icon="/com/intellij/uiDesigner/icons/splitPane.svg" removable="false" auto-create-binding="false" can-attach-label="false">
+        <default-constraints vsize-policy="3" hsize-policy="3" anchor="0" fill="3">
+          <preferred-size width="200" height="200" />
+        </default-constraints>
+      </item>
+      <item class="javax.swing.JSpinner" icon="/com/intellij/uiDesigner/icons/spinner.svg" removable="false" auto-create-binding="true" can-attach-label="true">
+        <default-constraints vsize-policy="0" hsize-policy="6" anchor="8" fill="1" />
+      </item>
+      <item class="javax.swing.JSlider" icon="/com/intellij/uiDesigner/icons/slider.svg" removable="false" auto-create-binding="true" can-attach-label="false">
+        <default-constraints vsize-policy="0" hsize-policy="6" anchor="8" fill="1" />
+      </item>
+      <item class="javax.swing.JSeparator" icon="/com/intellij/uiDesigner/icons/separator.svg" removable="false" auto-create-binding="false" can-attach-label="false">
+        <default-constraints vsize-policy="6" hsize-policy="6" anchor="0" fill="3" />
+      </item>
+      <item class="javax.swing.JProgressBar" icon="/com/intellij/uiDesigner/icons/progressbar.svg" removable="false" auto-create-binding="true" can-attach-label="false">
+        <default-constraints vsize-policy="0" hsize-policy="6" anchor="0" fill="1" />
+      </item>
+      <item class="javax.swing.JToolBar" icon="/com/intellij/uiDesigner/icons/toolbar.svg" removable="false" auto-create-binding="false" can-attach-label="false">
+        <default-constraints vsize-policy="0" hsize-policy="6" anchor="0" fill="1">
+          <preferred-size width="-1" height="20" />
+        </default-constraints>
+      </item>
+      <item class="javax.swing.JToolBar$Separator" icon="/com/intellij/uiDesigner/icons/toolbarSeparator.svg" removable="false" auto-create-binding="false" can-attach-label="false">
+        <default-constraints vsize-policy="0" hsize-policy="0" anchor="0" fill="1" />
+      </item>
+      <item class="javax.swing.JScrollBar" icon="/com/intellij/uiDesigner/icons/scrollbar.svg" removable="false" auto-create-binding="true" can-attach-label="false">
+        <default-constraints vsize-policy="6" hsize-policy="0" anchor="0" fill="2" />
+      </item>
+    </group>
+  </component>
+</project>
\ No newline at end of file
diff --git a/.idea/workspace.xml b/.idea/workspace.xml
index b2364b2..9771805 100644
--- a/.idea/workspace.xml
+++ b/.idea/workspace.xml
@@ -5,13 +5,21 @@
   </component>
   <component name="ChangeListManager">
     <list default="true" id="84a72837-59a8-41a4-880d-4655e858dd1b" name="Changes" comment="">
+      <change afterPath="$PROJECT_DIR$/diary.txt" afterDir="false" />
+      <change afterPath="$PROJECT_DIR$/trash.txt" afterDir="false" />
       <change beforePath="$PROJECT_DIR$/.idea/workspace.xml" beforeDir="false" afterPath="$PROJECT_DIR$/.idea/workspace.xml" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/src/main/java/org/sopt/week1/DiaryRepository.java" beforeDir="false" afterPath="$PROJECT_DIR$/src/main/java/org/sopt/week1/DiaryRepository.java" afterDir="false" />
+      <change beforePath="$PROJECT_DIR$/src/main/java/org/sopt/week1/TextUtils.java" beforeDir="false" afterPath="$PROJECT_DIR$/src/main/java/org/sopt/week1/TextUtils.java" afterDir="false" />
+
     </list>
     <option name="SHOW_DIALOG" value="false" />
     <option name="HIGHLIGHT_CONFLICTS" value="true" />
     <option name="HIGHLIGHT_NON_ACTIVE_CHANGELIST" value="false" />
     <option name="LAST_RESOLUTION" value="IGNORE" />
   </component>
+  <component name="CodeInsightWorkspaceSettings">
+    <option name="optimizeImportsOnTheFly" value="true" />
+  </component>
   <component name="ExternalProjectsData">
     <projectState path="$PROJECT_DIR$">
       <ProjectState />
@@ -36,6 +44,11 @@
               <option name="branches">
                 <list>
                   <RecentBranch>
+                    <option name="branchName" value="seminar-deep/#1" />
+                    <option name="lastUsedInstant" value="1728475998" />
+                  </RecentBranch>
+                  <RecentBranch>
+
                     <option name="branchName" value="seminar/#1" />
                     <option name="lastUsedInstant" value="1728112737" />
                   </RecentBranch>
@@ -66,27 +79,29 @@
   <component name="ProjectViewState">
     <option name="showLibraryContents" value="true" />
   </component>
-  <component name="PropertiesComponent">{
-  &quot;keyToString&quot;: {
-    &quot;Gradle.assignment [:Main.main()].executor&quot;: &quot;Run&quot;,
-    &quot;RunOnceActivity.OpenProjectViewOnStart&quot;: &quot;true&quot;,
-    &quot;RunOnceActivity.ShowReadmeOnStart&quot;: &quot;true&quot;,
-    &quot;git-widget-placeholder&quot;: &quot;seminar/#1&quot;,
-    &quot;kotlin-language-version-configured&quot;: &quot;true&quot;,
-    &quot;node.js.detected.package.eslint&quot;: &quot;true&quot;,
-    &quot;node.js.detected.package.tslint&quot;: &quot;true&quot;,
-    &quot;node.js.selected.package.eslint&quot;: &quot;(autodetect)&quot;,
-    &quot;node.js.selected.package.tslint&quot;: &quot;(autodetect)&quot;,
-    &quot;nodejs_package_manager_path&quot;: &quot;npm&quot;,
-    &quot;onboarding.tips.debug.path&quot;: &quot;/Users/a./Desktop/AND-SOPT/assignment/src/main/java/org/sopt/Main.java&quot;,
-    &quot;project.structure.last.edited&quot;: &quot;Project&quot;,
-    &quot;project.structure.proportion&quot;: &quot;0.0&quot;,
-    &quot;project.structure.side.proportion&quot;: &quot;0.0&quot;,
-    &quot;settings.editor.selected.configurable&quot;: &quot;org.jetbrains.plugins.github.ui.GithubSettingsConfigurable&quot;,
-    &quot;vue.rearranger.settings.migration&quot;: &quot;true&quot;
+  <component name="PropertiesComponent"><![CDATA[{
+  "keyToString": {
+    "Gradle.TextUtilsTest.이모지는_한_개의_문자로_인식한다.executor": "Run",
+    "Gradle.assignment [:Main.main()].executor": "Run",
+    "RunOnceActivity.OpenProjectViewOnStart": "true",
+    "RunOnceActivity.ShowReadmeOnStart": "true",
+    "git-widget-placeholder": "seminar-deep/#1",
+    "kotlin-language-version-configured": "true",
+    "node.js.detected.package.eslint": "true",
+    "node.js.detected.package.tslint": "true",
+    "node.js.selected.package.eslint": "(autodetect)",
+    "node.js.selected.package.tslint": "(autodetect)",
+    "nodejs_package_manager_path": "npm",
+    "onboarding.tips.debug.path": "/Users/a./Desktop/AND-SOPT/assignment/src/main/java/org/sopt/Main.java",
+    "project.structure.last.edited": "Project",
+    "project.structure.proportion": "0.0",
+    "project.structure.side.proportion": "0.0",
+    "settings.editor.selected.configurable": "editor.preferences.import",
+    "vue.rearranger.settings.migration": "true"
   }
-}</component>
-  <component name="RunManager">
+}]]></component>
+  <component name="RunManager" selected="Application.Main">
+
     <configuration name="Main" type="Application" factoryName="Application" temporary="true" nameIsGenerated="true">
       <option name="MAIN_CLASS_NAME" value="org.sopt.week1.Main" />
       <module name="assignment.main" />
@@ -100,8 +115,34 @@
         <option name="Make" enabled="true" />
       </method>
     </configuration>
+    <configuration name="TextUtilsTest.이모지는_한_개의_문자로_인식한다" type="GradleRunConfiguration" factoryName="Gradle" temporary="true">
+      <ExternalSystemSettings>
+        <option name="executionName" />
+        <option name="externalProjectPath" value="$PROJECT_DIR$" />
+        <option name="externalSystemIdString" value="GRADLE" />
+        <option name="scriptParameters" value="" />
+        <option name="taskDescriptions">
+          <list />
+        </option>
+        <option name="taskNames">
+          <list>
+            <option value=":test" />
+            <option value="--tests" />
+            <option value="&quot;TextUtilsTest.이모지는_한_개의_문자로_인식한다&quot;" />
+          </list>
+        </option>
+        <option name="vmOptions" />
+      </ExternalSystemSettings>
+      <ExternalSystemDebugServerProcess>false</ExternalSystemDebugServerProcess>
+      <ExternalSystemReattachDebugProcess>true</ExternalSystemReattachDebugProcess>
+      <DebugAllEnabled>false</DebugAllEnabled>
+      <RunAsTest>true</RunAsTest>
+      <method v="2" />
+    </configuration>
     <recent_temporary>
       <list>
+        <item itemvalue="Gradle.TextUtilsTest.이모지는_한_개의_문자로_인식한다" />
+
         <item itemvalue="Application.Main" />
       </list>
     </recent_temporary>
@@ -126,6 +167,10 @@
       <workItem from="1728384645457" duration="726000" />
       <workItem from="1728394538026" duration="8959000" />
       <workItem from="1728471866285" duration="410000" />
+      <workItem from="1728475699985" duration="2394000" />
+      <workItem from="1728517555087" duration="1132000" />
+      <workItem from="1728519518119" duration="4978000" />
+
     </task>
     <servers />
   </component>
@@ -143,7 +188,8 @@
                   <entry key="branch">
                     <value>
                       <list>
-                        <option value="seminar/#1" />
+                        <option value="seminar-deep/#1" />
+
                       </list>
                     </value>
                   </entry>
diff --git a/diary.txt b/diary.txt
new file mode 100644
index 0000000..3397f58
--- /dev/null
+++ b/diary.txt
@@ -0,0 +1,4 @@
+1 test
+3 test3
+4 testest
+2 update
diff --git a/id.txt b/id.txt
new file mode 100644
index 0000000..bf0d87a
--- /dev/null
+++ b/id.txt
@@ -0,0 +1 @@
+4
\ No newline at end of file
diff --git a/src/main/java/org/sopt/week1/DiaryController.java b/src/main/java/org/sopt/week1/DiaryController.java
index d2f2463..c505c2f 100644
--- a/src/main/java/org/sopt/week1/DiaryController.java
+++ b/src/main/java/org/sopt/week1/DiaryController.java
@@ -24,8 +24,9 @@ final List<Diary> getList() {
     }
 
     final void post(final String body) {
-        if (body.length() > 30) {
-            throw new IllegalArgumentException();
+        if (TextUtils.getLengthOfBody(body) > 30) {
+            throw new IllegalArgumentException("30자 이하로 적어주세요");
+
         }
         diaryService.writeDiary(body);
     }
@@ -38,6 +39,11 @@ final void patch(final String id, final String body) {
         diaryService.updateDiary(Long.parseLong(id), body);
     }
 
+    final void restore() {
+        diaryService.restoreDiaryList();
+    }
+
+
     enum Status {
         READY,
         RUNNING,
diff --git a/src/main/java/org/sopt/week1/DiaryRepository.java b/src/main/java/org/sopt/week1/DiaryRepository.java
index ae8699d..4e8b09c 100644
--- a/src/main/java/org/sopt/week1/DiaryRepository.java
+++ b/src/main/java/org/sopt/week1/DiaryRepository.java
@@ -1,44 +1,215 @@
 package org.sopt.week1;
 
+import java.io.*;
 import java.util.ArrayList;
-import java.util.HashMap;
 import java.util.List;
-import java.util.Map;
-import java.util.concurrent.ConcurrentHashMap;
-import java.util.concurrent.atomic.AtomicLong;
 
 public class DiaryRepository {
-    private final Map<Long, String> storage = new ConcurrentHashMap<>();
-    private final AtomicLong numbering = new AtomicLong();
+    File diaryFile = new File("diary.txt");
+    File idFile = new File("id.txt");
+    File trashFile = new File("trash.txt");
+    File tempFile = new File("tempDiary.txt");
 
     void save(final Diary diary) {
-        // 채번 과정
-        final long id = numbering.addAndGet(1);
-        // 저장 과정
-        storage.put(id, diary.getBody());
+
+        long lastId = loadLastId();
+        final long id = lastId + 1;
+
+        try {
+            BufferedWriter bufferedWriter = new BufferedWriter(new FileWriter(diaryFile, true));
+
+            if (diaryFile.isFile() && diaryFile.canWrite()) {
+                bufferedWriter.write(id + " " + diary.getBody());
+                bufferedWriter.newLine();
+                bufferedWriter.close();
+            }
+
+            saveLastId(id);
+
+        } catch (IOException e) {
+            System.out.println(e.getMessage());
+        }
     }
 
     List<Diary> findAll() {
-        // (1) diary를 담을 자료구조
         final List<Diary> diaryList = new ArrayList<>();
-        // (2) 저장한 값을 불러오는 반복 구조
-        for (long index = 1; index <= numbering.intValue(); index++) {
-            final String body = storage.get(index);
-            // (2-1) 저장한 값을 불러오는 반복 구조
-            if (body != null) {
-                diaryList.add(new Diary(index, body));
+
+        try {
+            FileReader fileReader = new FileReader(diaryFile);
+            BufferedReader bufferedReader = new BufferedReader(fileReader);
+            String diaryFileInfo = "";
+
+            while ((diaryFileInfo = bufferedReader.readLine()) != null) {
+                List<String> diaryInfo = TextUtils.splitDiaryInfo(diaryFileInfo);
+                diaryList.add(new Diary(Long.parseLong(diaryInfo.get(0)), diaryInfo.get(1)));
             }
+
+        } catch (IOException e) {
+            System.out.println(e.getMessage());
         }
-        // (3) 불러온 자료구조를 응답
         return diaryList;
     }
 
     void deleteById(final Long id) {
-        storage.remove(id);
+        isValidateId(id);
+        try {
+            // diaryFile에서 삭제할 ID를 제외하고 임시 파일에 저장
+            BufferedWriter tempWriter = new BufferedWriter(new FileWriter(tempFile));
+            BufferedReader diaryReader = new BufferedReader(new FileReader(diaryFile));
+            BufferedWriter trashWriter = new BufferedWriter(new FileWriter(trashFile, true));
+
+            String currentLine;
+            boolean isFound = false;
+
+            while ((currentLine = diaryReader.readLine()) != null) {
+                List<String> diaryInfo = TextUtils.splitDiaryInfo(currentLine);
+                if (diaryInfo.get(0).equals(id.toString())) {
+                    // 삭제할 Diary를 trash.txt에 저장
+                    trashWriter.write(currentLine);
+                    trashWriter.newLine();
+                    isFound = true;  // ID를 찾았음을 표시
+                } else {
+                    tempWriter.write(currentLine);
+                    tempWriter.newLine();
+                }
+            }
+
+            tempWriter.close();
+            diaryReader.close();
+            trashWriter.close();
+
+            // ID가 존재했으면 임시 파일을 원본 파일로 대체
+            if (isFound) {
+                diaryFile.delete();
+                tempFile.renameTo(diaryFile);
+            } else {
+                // ID가 존재하지 않을 경우 임시 파일을 삭제
+                tempFile.delete();
+                throw new IllegalArgumentException("해당 ID의 Diary가 존재하지 않습니다.");
+            }
+
+        } catch (IOException e) {
+            System.out.println(e.getMessage());
+        }
     }
 
     void updateById(final Long id, final String body) {
-        storage.replace(id, body);
+        isValidateId(id);
+        try {
+            BufferedWriter tempWriter = new BufferedWriter(new FileWriter(tempFile));
+            BufferedReader diaryReader = new BufferedReader(new FileReader(diaryFile));
+
+            String currentLine;
+            boolean isFound = false;
+
+            while ((currentLine = diaryReader.readLine()) != null) {
+                List<String> diaryInfo = TextUtils.splitDiaryInfo(currentLine);
+                if (diaryInfo.get(0).equals(id.toString())) {
+                    // 수정된 내용으로 기록
+                    tempWriter.write(id + " " + body);
+                    tempWriter.newLine();
+                    isFound = true;  // ID를 찾았음을 표시
+                } else {
+                    tempWriter.write(currentLine);
+                    tempWriter.newLine();
+                }
+            }
+
+            tempWriter.close();
+            diaryReader.close();
+
+            // ID가 존재했으면 임시 파일을 원본 파일로 대체
+            if (isFound) {
+                diaryFile.delete();
+                tempFile.renameTo(diaryFile);
+            } else {
+                // ID가 존재하지 않을 경우 임시 파일을 삭제
+                tempFile.delete();
+                throw new IllegalArgumentException("해당 ID의 Diary가 존재하지 않습니다.");
+            }
+
+        } catch (IOException e) {
+            System.out.println(e.getMessage());
+        }
+    }
+
+    void restoreAll() {
+        try {
+            BufferedReader trashReader = new BufferedReader(new FileReader(trashFile));
+            BufferedWriter diaryWriter = new BufferedWriter(new FileWriter(diaryFile, true)); // append mode로 diary.txt에 추가
+
+            String currentLine;
+            boolean isRestored = false;
+
+            while ((currentLine = trashReader.readLine()) != null) {
+                diaryWriter.write(currentLine);
+                diaryWriter.newLine();
+                isRestored = true; // 복원 작업이 있음을 표시
+            }
+
+            trashReader.close();
+            diaryWriter.close();
+
+            // 복원이 완료되었으면 trash.txt 파일 비우기
+            if (isRestored) {
+                BufferedWriter trashCleaner = new BufferedWriter(new FileWriter(trashFile)); // trash.txt 초기화
+                trashCleaner.write("");
+                trashCleaner.close();
+            }
+
+        } catch (IOException e) {
+            System.out.println(e.getMessage());
+        }
+    }
+
+
+    void isValidateId(final Long id) {
+        List<Long> diaryIds = new ArrayList<Long>();
+
+        try {
+            FileReader fileReader = new FileReader(diaryFile);
+            BufferedReader bufferedReader = new BufferedReader(fileReader);
+            String diaryFileInfo = "";
+
+
+            while ((diaryFileInfo = bufferedReader.readLine()) != null) {
+                List<String> diaryInfo = TextUtils.splitDiaryInfo(diaryFileInfo);
+                diaryIds.add(Long.parseLong(diaryInfo.get(0)));
+            }
+        } catch (IOException e) {
+            System.out.println(e.getMessage());
+        }
+        if (!diaryIds.contains(id)) {
+            throw new IllegalArgumentException("존재하지 않는 일기 id입니다.");
+        }
+    }
+
+    private long loadLastId() {
+        long lastId = 0;
+        if (idFile.exists()) {
+            try {
+                BufferedReader bufferedReader = new BufferedReader(new FileReader(idFile));
+                String idStr = bufferedReader.readLine();  // ID 값을 한 줄로 저장
+                if (idStr != null) {
+                    lastId = Long.parseLong(idStr);
+                }
+                bufferedReader.close();
+            } catch (IOException e) {
+                System.out.println(e.getMessage());
+            }
+        }
+        return lastId;
+    }
+
+    private void saveLastId(long id) {
+        try {
+            BufferedWriter bufferedWriter = new BufferedWriter(new FileWriter(idFile));
+            bufferedWriter.write(Long.toString(id));
+            bufferedWriter.close();
+        } catch (IOException e) {
+            System.out.println(e.getMessage());
+        }
+
     }
 
 }
diff --git a/src/main/java/org/sopt/week1/DiaryService.java b/src/main/java/org/sopt/week1/DiaryService.java
index 96aa495..0fae86b 100644
--- a/src/main/java/org/sopt/week1/DiaryService.java
+++ b/src/main/java/org/sopt/week1/DiaryService.java
@@ -23,4 +23,8 @@ void updateDiary(final Long id, final String body) {
         diaryRepository.updateById(id, body);
     }
 
+    void restoreDiaryList() {
+        diaryRepository.restoreAll();
+    }
+
 }
diff --git a/src/main/java/org/sopt/week1/Main.java b/src/main/java/org/sopt/week1/Main.java
index 1b4df8e..7dca3bc 100644
--- a/src/main/java/org/sopt/week1/Main.java
+++ b/src/main/java/org/sopt/week1/Main.java
@@ -46,6 +46,9 @@ public void runRepeatedly() throws IOException {
                     run();
                 } catch (InvalidInputException e) {
                     ConsoleIO.printLine("잘못된 값을 입력하였습니다.");
+                } catch (IllegalArgumentException e) {
+                    ConsoleIO.printLine(e.getMessage());
+
                 }
 
                 if (isFinished()) {
@@ -92,6 +95,12 @@ private void run() throws IOException {
 
                             server.patch(inputId, inputBody);
                         }
+                        case "RESTORE" -> {
+                            server.restore();
+
+                            ConsoleIO.printLine("삭제된 일기를 복구했습니다.");
+                        }
+
                         case "FINISH" -> {
                             server.finish();
                         }
@@ -123,6 +132,8 @@ private String getMenu() {
                     - POST : 일기 작성하기
                     - DELETE : 일기 제거하기
                     - PATCH : 일기 수정하기
+                    - RESTORE : 일기 복구하기
+
                     """;
 
         }
diff --git a/src/main/java/org/sopt/week1/TextUtils.java b/src/main/java/org/sopt/week1/TextUtils.java
new file mode 100644
index 0000000..6abd078
--- /dev/null
+++ b/src/main/java/org/sopt/week1/TextUtils.java
@@ -0,0 +1,31 @@
+package org.sopt.week1;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+public class TextUtils {
+
+    private static final Pattern graphemePattern = Pattern.compile("\\X");
+    private static final Matcher graphemeMatcher = graphemePattern.matcher("");
+    private static final String SPLIT_CHARACTERS = " ";
+
+    public static int getLengthOfBody(final String body) {
+        if (body == null) {
+            return 0;
+        }
+
+        graphemeMatcher.reset(body);
+
+        int count = 0;
+        while (graphemeMatcher.find()) {
+            count++;
+        }
+        return count;
+    }
+
+    public static List<String> splitDiaryInfo(String diaryInfo) {
+        return new ArrayList<String>(List.of(diaryInfo.split(SPLIT_CHARACTERS)));
+    }
+}
diff --git a/src/test/java/TextUtilsTest.java b/src/test/java/TextUtilsTest.java
new file mode 100644
index 0000000..aa7d035
--- /dev/null
+++ b/src/test/java/TextUtilsTest.java
@@ -0,0 +1,25 @@
+import org.junit.jupiter.api.*;
+import org.sopt.week1.TextUtils;
+
+@DisplayName("일기 글자 수 세기 테스트")
+@DisplayNameGeneration(DisplayNameGenerator.ReplaceUnderscores.class)
+public class TextUtilsTest {
+
+    @Test
+    void 이모지는_한_개의_문자로_인식한다() {
+        //given
+        final String test1 = "😃행복한 하루였어요👍";
+        final String test2 = "🤞🏻🤞🏻🤞🏻🤞🏻🤞🏻🤞🏻🤞🏻🤞🏻🤞🏻🤞🏻🤞🏻🤞🏻🤞🏻🤞🏻🤞🏻🤞🏻🤞🏻🤞🏻🤞🏻🤞🏻🤞🏻🤞🏻🤞🏻🤞🏻🤞🏻🤞🏻🤞🏻🤞🏻🤞🏻🤞🏻🤞🏻";
+        final int expected1 = 11;
+        final int expected2 = 31;
+
+        //when
+        final int actual1 = TextUtils.getLengthOfBody(test1);
+        final int actual2 = TextUtils.getLengthOfBody(test2);
+
+        //then
+        Assertions.assertEquals(actual1, expected1);
+        Assertions.assertEquals(actual2, expected2);
+
+    }
+}
diff --git a/trash.txt b/trash.txt
new file mode 100644
index 0000000..e69de29