A transmitting/receiving apparatus of down-link data using an automatic repeat request (ARQ) scheme and a method thereof in a wireless communication system is provided. In order to send an ARQ feedback message between a base station and a terminal without a radio resource allocation process in a wireless communication system, when the base station receives down-link data from the terminal of the base station, the base station stores the number list of the transmitted frames and periodically detects the list and automatically allocates radio resources for up-link without an additional process when the list is larger than a predetermined frame. The radio resource allocation request process can be omitted because a radio resource is automatically allocated during the up-link period after the base station transmits the down-link traffic. Thus, the response speed of an ARQ feedback acknowledgement message is enhanced, thereby enhancing a down-link transmission speed.