diff --git a/Assets/QuickSheet/Editor/BaseMachine.cs b/Assets/QuickSheet/Editor/BaseMachine.cs
index ff11b28..a0ae8cd 100644
--- a/Assets/QuickSheet/Editor/BaseMachine.cs
+++ b/Assets/QuickSheet/Editor/BaseMachine.cs
@@ -13,13 +13,13 @@
 namespace UnityQuickSheet
 {
     [System.Serializable]
-    public class HeaderColumn
+    public class ColumnHeader
     {
         public CellType type;
         public string name;
         public bool isEnable;
         public bool isArray;
-        public HeaderColumn nextArrayItem;
+        public ColumnHeader nextArrayItem;
 
         // used to order columns by ascending. (only need on excel-plugin)
         public int OrderNO { get; set; }
@@ -100,22 +100,22 @@ public string WorkSheetName
         [System.NonSerialized]
         public bool onlyCreateDataClass = false;
 
-        public List<HeaderColumn> HeaderColumnList
+        public List<ColumnHeader> ColumnHeaderList
         {
-            get { return headerColumnList; }
-            set { headerColumnList = value;}
+            get { return columnHeaderList; }
+            set { columnHeaderList = value; }
         }
 
         [SerializeField]
-        protected List<HeaderColumn> headerColumnList;
+        protected List<ColumnHeader> columnHeaderList;
 
         /// <summary>
         /// Return true, if the list is instantiated and has any its item more than one.
         /// </summary>
         /// <returns></returns>
-        public bool HasHeadColumn()
+        public bool HasColumnHeader()
         {
-            if (headerColumnList != null && headerColumnList.Count > 0)
+            if (columnHeaderList != null && columnHeaderList.Count > 0)
                 return true;
 
             return false;
@@ -126,8 +126,8 @@ public bool HasHeadColumn()
 
         protected void OnEnable()
         {
-            if (headerColumnList == null)
-                headerColumnList = new List<HeaderColumn>();
+            if (columnHeaderList == null)
+                columnHeaderList = new List<ColumnHeader>();
         }
 
         /// <summary>
diff --git a/Assets/QuickSheet/Editor/BaseMachineEditor.cs b/Assets/QuickSheet/Editor/BaseMachineEditor.cs
index 80fa36f..618bd23 100644
--- a/Assets/QuickSheet/Editor/BaseMachineEditor.cs
+++ b/Assets/QuickSheet/Editor/BaseMachineEditor.cs
@@ -180,7 +180,7 @@ protected void CreateDataClassScript(BaseMachine machine, ScriptPrescription sp)
             List<MemberFieldData> fieldList = new List<MemberFieldData>();
 
             //FIXME: replace ValueType to CellType and support Enum type.
-            foreach (HeaderColumn header in machine.HeaderColumnList)
+            foreach (ColumnHeader header in machine.ColumnHeaderList)
             {
                 MemberFieldData member = new MemberFieldData();
                 member.Name = header.name;
@@ -283,7 +283,7 @@ protected string GetAbsoluteBuiltinTemplatePath()
 
         protected void DrawHeaderSetting(BaseMachine m)
         {
-            if (m.HasHeadColumn())
+            if (m.HasColumnHeader())
             {
                 GUIStyle headerStyle = GUIHelper.MakeHeader();
                 GUILayout.Label("Type Settings:", headerStyle);
@@ -304,7 +304,7 @@ protected void DrawHeaderSetting(BaseMachine m)
                 EditorGUILayout.BeginVertical("box");
 
                 //string lastCellName = string.Empty;
-                foreach (HeaderColumn header in m.HeaderColumnList)
+                foreach (ColumnHeader header in m.ColumnHeaderList)
                 {
                     GUILayout.BeginHorizontal();
 
diff --git a/Assets/QuickSheet/ExcelPlugin/Editor/ExcelMachineEditor.cs b/Assets/QuickSheet/ExcelPlugin/Editor/ExcelMachineEditor.cs
index 30fe084..262d2de 100644
--- a/Assets/QuickSheet/ExcelPlugin/Editor/ExcelMachineEditor.cs
+++ b/Assets/QuickSheet/ExcelPlugin/Editor/ExcelMachineEditor.cs
@@ -125,7 +125,7 @@ Set a folder under the 'Assets' folder! \n
 
             GUILayout.BeginHorizontal();
 
-            if (machine.HasHeadColumn())
+            if (machine.HasColumnHeader())
             {
                 if (GUILayout.Button("Update"))
                     Import();
@@ -232,36 +232,36 @@ protected override void Import(bool reimport = false)
 
             List<string> titleList = titles.ToList();
 
-            if (machine.HasHeadColumn() && reimport == false)
+            if (machine.HasColumnHeader() && reimport == false)
             {
-                var headerDic = machine.HeaderColumnList.ToDictionary(header => header.name);
+                var headerDic = machine.ColumnHeaderList.ToDictionary(header => header.name);
 
                 // collect non-changed column headers
                 var exist = from t in titleList
                             where headerDic.ContainsKey(t) == true
-                            select new HeaderColumn { name = t, type = headerDic[t].type, isArray = headerDic[t].isArray, OrderNO = headerDic[t].OrderNO };
+                            select new ColumnHeader { name = t, type = headerDic[t].type, isArray = headerDic[t].isArray, OrderNO = headerDic[t].OrderNO };
 
                 // collect newly added or changed column headers
                 var changed = from t in titleList
                               where headerDic.ContainsKey(t) == false
-                              select new HeaderColumn { name = t, type = CellType.Undefined, OrderNO = titleList.IndexOf(t) };
+                              select new ColumnHeader { name = t, type = CellType.Undefined, OrderNO = titleList.IndexOf(t) };
 
                 // merge two list via LINQ
                 var merged = exist.Union(changed).OrderBy(x => x.OrderNO);
 
-                machine.HeaderColumnList.Clear();
-                machine.HeaderColumnList = merged.ToList();
+                machine.ColumnHeaderList.Clear();
+                machine.ColumnHeaderList = merged.ToList();
             }
             else
             {
-                machine.HeaderColumnList.Clear();
+                machine.ColumnHeaderList.Clear();
 
                 if (titles != null)
                 {
                     int i = 0;
                     foreach (string s in titles)
                     {
-                        machine.HeaderColumnList.Add(new HeaderColumn { name = s, type = CellType.Undefined, OrderNO = i });
+                        machine.ColumnHeaderList.Add(new ColumnHeader { name = s, type = CellType.Undefined, OrderNO = i });
                         i++;
                     }
                 }
diff --git a/Assets/QuickSheet/GDataPlugin/Editor/GoogleMachineEditor.cs b/Assets/QuickSheet/GDataPlugin/Editor/GoogleMachineEditor.cs
index a4111fc..fe5dadb 100644
--- a/Assets/QuickSheet/GDataPlugin/Editor/GoogleMachineEditor.cs
+++ b/Assets/QuickSheet/GDataPlugin/Editor/GoogleMachineEditor.cs
@@ -101,7 +101,7 @@ public override void OnInspectorGUI()
 
             GUILayout.BeginHorizontal();
 
-            if (machine.HasHeadColumn())
+            if (machine.HasColumnHeader())
             {
                 if (GUILayout.Button("Update"))
                     Import();
@@ -201,13 +201,13 @@ protected override void Import(bool reimport = false)
 
             Regex re = new Regex(@"\d+");
 
-            Dictionary<string, HeaderColumn> headerDic = null;
+            Dictionary<string, ColumnHeader> headerDic = null;
             if (reimport)
-                machine.HeaderColumnList.Clear();
+                machine.ColumnHeaderList.Clear();
             else
-                headerDic = machine.HeaderColumnList.ToDictionary(k => k.name);
+                headerDic = machine.ColumnHeaderList.ToDictionary(k => k.name);
 
-            List<HeaderColumn> tmpColumnList = new List<HeaderColumn>();
+            List<ColumnHeader> tmpColumnList = new List<ColumnHeader>();
 
             // query the first columns only.
             DoCellQuery((cell) =>
@@ -228,12 +228,12 @@ protected override void Import(bool reimport = false)
                     return;
                 }
 
-                HeaderColumn column = new HeaderColumn();
+                ColumnHeader column = new ColumnHeader();
                 column.name = cell.Value;
                 if (headerDic != null && headerDic.ContainsKey(cell.Value))
                 {
                     // if the column is already exist, copy its name and type from the exist one.
-                    HeaderColumn h = machine.HeaderColumnList.Find(x => x.name == column.name);
+                    ColumnHeader h = machine.ColumnHeaderList.Find(x => x.name == column.name);
                     if (h != null)
                     {
                         column.type = h.type;
@@ -249,7 +249,7 @@ protected override void Import(bool reimport = false)
             });
 
             // update (all of settings are reset when it reimports)
-            machine.HeaderColumnList = tmpColumnList;
+            machine.ColumnHeaderList = tmpColumnList;
 
             EditorUtility.SetDirty(machine);
             AssetDatabase.SaveAssets();