A BTS 100 includes a MAC-hs processing unit configured to determine if the priority of a communication to be executed for the communication request received is equal to or higher than a predetermined priority, and a HARQ process control unit 121 configured to assign a priority communication to be executed for the communication request to the retransmission processes in preference to other communications if the determination unit determines that the priority is equal to or higher than the predetermined priority. In a case where all the retransmission processes are occupied by the other communications, the HARQ process control unit 121 discards some of the packets stored in a HARQ buffer, based on the number of the retransmission processes required for executing the priority communication.