diff --git a/src/class.c b/src/class.c
index 65d8cd3fb..cc13a9ef3 100644
--- a/src/class.c
+++ b/src/class.c
@@ -351,8 +351,7 @@ mrb_const_name_p(mrb_state *mrb, const char *name, mrb_int len)
 static void
 setup_class(mrb_state *mrb, struct RClass *outer, struct RClass *c, mrb_sym id)
 {
-  mrb_class_name_class(mrb, outer, c, id);
-  mrb_obj_iv_set(mrb, (struct RObject*)outer, id, mrb_obj_value(c));
+  mrb_const_set(mrb, mrb_obj_value(outer), id, mrb_obj_value(c));
 }
 
 #define make_metaclass(mrb, c) prepare_singleton_class((mrb), (struct RBasic*)(c))