diff --git a/ext/tk/lib/tk.rb b/ext/tk/lib/tk.rb
index d282bbd5ea..0941635716 100644
--- a/ext/tk/lib/tk.rb
+++ b/ext/tk/lib/tk.rb
@@ -4532,7 +4532,7 @@ class TkScale<TkWindow
     elsif slot.kind_of?(Hash) && 
 	(slot.key?('command') || slot.key?(:command))
       slot = _symbolkey2str(slot)
-      slot['command'] = __wrap_command_arg(slot.delete('command'))
+      slot['command'] = _wrap_command_arg(slot.delete('command'))
     end
     super(slot, value)
   end