diff --git a/optuna_dashboard/serializer.py b/optuna_dashboard/serializer.py
index de733a4b..5002180a 100644
--- a/optuna_dashboard/serializer.py
+++ b/optuna_dashboard/serializer.py
@@ -6,7 +6,7 @@ from optuna.trial import FrozenTrial
 
 try:
     from typing import TypedDict
-except:
+except ImportError:
     from typing_extensions import TypedDict