diff --git a/src/api/types.ts b/src/api/types.ts
index 8e28f7b98..c990c42b6 100644
--- a/src/api/types.ts
+++ b/src/api/types.ts
@@ -7386,7 +7386,7 @@ export interface AnalysisKeywordTokenizer extends AnalysisTokenizerBase {
 
 export interface AnalysisKuromojiAnalyzer {
   type: 'kuromoji'
-  mode: AnalysisKuromojiTokenizationMode
+  mode?: AnalysisKuromojiTokenizationMode
   user_dictionary?: string
 }