diff --git a/mrbgems/mruby-toplevel-ext/mrblib/toplevel.rb b/mrbgems/mruby-toplevel-ext/mrblib/toplevel.rb
index 24a042e84..774562398 100644
--- a/mrbgems/mruby-toplevel-ext/mrblib/toplevel.rb
+++ b/mrbgems/mruby-toplevel-ext/mrblib/toplevel.rb
@@ -1,6 +1,6 @@
 
 def self.include (*modules)
-  self.class.include *modules
+  self.class.include(*modules)
 end
 
 def self.private(*methods)