diff --git a/apps/inm/serializers.py b/apps/inm/serializers.py
index 881315b8..2e4b7b26 100644
--- a/apps/inm/serializers.py
+++ b/apps/inm/serializers.py
@@ -231,7 +231,7 @@ class MIODoSerializer(CustomModelSerializer):
         fields = ['id', 'number', 'note', 'do_user',
                   'belong_dept', 'type', 'inout_date', 'mgroup', 'mio_user']
         extra_kwargs = {'inout_date': {'required': True}, 
-                        'do_user': {'required': True}}
+                        'do_user': {'required': True}, 'belong_dept': {'required': False}}
         read_only_fields = ["number"]
 
     def validate(self, attrs):