diff --git a/mrbgems/mruby-enumerator/mrblib/enumerator.rb b/mrbgems/mruby-enumerator/mrblib/enumerator.rb
index 9abaca38a8..1515a7a892 100644
--- a/mrbgems/mruby-enumerator/mrblib/enumerator.rb
+++ b/mrbgems/mruby-enumerator/mrblib/enumerator.rb
@@ -516,6 +516,7 @@ def feed(value)
 
   # just for internal
   class Generator
+    include Enumerable
     def initialize(&block)
       raise TypeError, "wrong argument type #{self.class} (expected Proc)" unless block.kind_of? Proc