diff --git a/plugins/analysis-kuromoji/src/main/java/org/opensearch/index/analysis/KuromojiCompletionFilterFactory.java b/plugins/analysis-kuromoji/src/main/java/org/opensearch/index/analysis/KuromojiCompletionFilterFactory.java
index 3c6a1132b1e9b..1459c19de46db 100644
--- a/plugins/analysis-kuromoji/src/main/java/org/opensearch/index/analysis/KuromojiCompletionFilterFactory.java
+++ b/plugins/analysis-kuromoji/src/main/java/org/opensearch/index/analysis/KuromojiCompletionFilterFactory.java
@@ -25,11 +25,14 @@ public KuromojiCompletionFilterFactory(IndexSettings indexSettings, Environment
 
     public static Mode getMode(Settings settings) {
         String modeSetting = settings.get("mode", null);
-        if (modeSetting == null || "index".equalsIgnoreCase(modeSetting)) {
-            return Mode.INDEX;
-        } else {
-            return Mode.QUERY;
+        if (modeSetting != null) {
+            if ("index".equalsIgnoreCase(modeSetting)) {
+                return Mode.INDEX;
+            } else if ("query".equalsIgnoreCase(modeSetting)) {
+                return Mode.QUERY;
+            }
         }
+        return Mode.INDEX;
     }
 
     @Override