diff --git a/apps/chat/serializers/presign.py b/apps/chat/serializers/presign.py
index ac25f71..a4fc0ac 100644
--- a/apps/chat/serializers/presign.py
+++ b/apps/chat/serializers/presign.py
@@ -3,6 +3,7 @@ from rest_framework import serializers
 
 class SignContentSerializer(serializers.Serializer):
     filename = serializers.CharField()
+    content_type = serializers.CharField()
 
 
 class PresignResultSerializer(serializers.Serializer):