diff --git a/BACKEND/app/services/line_connection.ts b/BACKEND/app/services/line_connection.ts
index f8ca4ae..5585dcb 100644
--- a/BACKEND/app/services/line_connection.ts
+++ b/BACKEND/app/services/line_connection.ts
@@ -909,7 +909,7 @@ export default class LineConnection {
       }
 
       const payload = {
-        model: 'gpt-4o-mini',
+        model: 'gpt-5-mini',
         max_tokens: 1000,
         messages: [
           {