diff --git a/hb_server/apps/mtm/serializers.py b/hb_server/apps/mtm/serializers.py
index 46d5f87..b23fcef 100644
--- a/hb_server/apps/mtm/serializers.py
+++ b/hb_server/apps/mtm/serializers.py
@@ -98,7 +98,7 @@ class InputMaterialUpdateSerializer(serializers.ModelSerializer):
 class OutputMaterialSerializer(serializers.ModelSerializer):
     class Meta:
         model = OutputMaterial
-        fields = ['count', 'sort', 'material', 'subproduction']
+        fields = ['count', 'sort', 'material', 'subproduction', 'is_main']
     
     def create(self, validated_data):
         if OutputMaterial.objects.filter(subproduction=validated_data['subproduction'], is_deleted=False, is_main=True).exists():
@@ -110,7 +110,7 @@ class OutputMaterialSerializer(serializers.ModelSerializer):
 class OutputMaterialUpdateSerializer(serializers.ModelSerializer):
     class Meta:
         model = OutputMaterial
-        fields = ['count', 'sort']
+        fields = ['count', 'sort', 'is_main']
 
 class UsedStepCreateSerializer(serializers.ModelSerializer):
     """