diff --git a/migrator/migrator.go b/migrator/migrator.go
index cec4e30f..c0e739a7 100644
--- a/migrator/migrator.go
+++ b/migrator/migrator.go
@@ -531,7 +531,7 @@ func (m Migrator) MigrateColumn(value interface{}, field *schema.Field, columnTy
 	}
 
 	// check default value
-	if !field.PrimaryKey {
+	if !alterColumn && !field.PrimaryKey {
 		currentDefaultNotNull := field.HasDefaultValue && (field.DefaultValueInterface != nil || !strings.EqualFold(field.DefaultValue, "NULL"))
 		dv, dvNotNull := columnType.DefaultValue()
 		if dvNotNull && !currentDefaultNotNull {