A resource allocation method for a HARQ is disclosed. This resource allocation method includes, transmitting an MAP message having specific information indicating whether or not a differential allocation is supported, storing MAP information contained in the MAP message during a predetermined frame, and upon receiving an NACK message during the predetermined frame, transmitting sub-burst information having differential allocation information related to sub-bursts to be retransmitted. If there are a large amount of HARQ traffics, each embodiment of the present invention transmits only differential information on the basis of MAP information of the initial MAP message when HARQ sub-bursts is retransmitted.