diff --git a/ext/json/generator/generator.c b/ext/json/generator/generator.c
index e59a120008..036205d7cb 100644
--- a/ext/json/generator/generator.c
+++ b/ext/json/generator/generator.c
@@ -692,7 +692,7 @@ static VALUE cState_aref(VALUE self, VALUE name)
     if (RTEST(rb_funcall(self, i_respond_to_p, 1, name))) {
         return rb_funcall(self, i_send, 1, name);
     } else {
-        return rb_ivar_get(self, rb_intern_str(rb_str_concat(rb_str_new2("@"), name)));
+        return rb_attr_get(self, rb_intern_str(rb_str_concat(rb_str_new2("@"), name)));
     }
 }