In radio communication, the throughput reduction of a whole radio communication system caused by discarding retransmission data at the time of handover is prevented. The system includes a radio terminal for conducting data transmission and reception with a radio base station by executing one or more processes, a process executer in the radio base station for executing processes depending upon a number of processes executed in the radio terminal, and transmitting/receiving data to/from the radio terminal, a handover monitor in the radio base station for monitoring for the occurrence of handover or for the possibility of occurrence of handover in the radio terminal, and a process number controller in the radio base station for controlling the number of processes executed by the process executer according to a result of monitoring conducted by the handover monitor.