The present invention relates to a resource allocation device for efficiently using resources by persistently allocating the resources in a wireless communication system, and a method thereof. In the method, a quality of service (QoS) configuration is received according to a predetermined service, persistent resource allocation is performed according to a resource allocation request corresponding to the QoS configuration, various retransmission methods are determined when performing the persistent resource allocation, transmission data are established according to the determined retransmission method, and the transmission data are transmitted.