diff --git a/cpp/src/msgpack/type/define.hpp.erb b/cpp/src/msgpack/type/define.hpp.erb
index 9db6f088..011d2281 100644
--- a/cpp/src/msgpack/type/define.hpp.erb
+++ b/cpp/src/msgpack/type/define.hpp.erb
@@ -50,7 +50,7 @@ struct define<> {
 	template <typename Packer>
 	void msgpack_pack(Packer& pk) const
 	{
-		pk.pack_array(1);
+		pk.pack_array(0);
 	}
 	void msgpack_unpack(msgpack::object o)
 	{