diff --git a/apps/pm/serializers.py b/apps/pm/serializers.py
index b714e924..a238be34 100644
--- a/apps/pm/serializers.py
+++ b/apps/pm/serializers.py
@@ -31,7 +31,7 @@ class UtaskSerializer(CustomModelSerializer):
 
 
 class MtaskSerializer(CustomModelSerializer):
-    material_out_ = MaterialSerializer(source='material', read_only=True)
+    material_out_ = MaterialSerializer(source='material_out', read_only=True)
     mgroup_name = serializers.CharField(source='mgroup.name', read_only=True)
 
     class Meta: