diff --git a/apps/edu/views.py b/apps/edu/views.py
index 1d47310d..b18112bd 100644
--- a/apps/edu/views.py
+++ b/apps/edu/views.py
@@ -73,7 +73,9 @@ class ExamViewSet(CustomModelViewSet):
         if has_perm(self.request.user, ["exam.view"]):
             return qs
         user:User = self.request.user
-        dept = user.belong_dept if user else None
+        dept = None
+        if user.is_authenticated:
+            dept = user.belong_dept
         qs = qs.filter(is_public=True)
         qs = qs|qs.filter(p_users=user)
         if dept: