To provide a system by which a moving station does not need to simultaneously transmit/receive two or more carrier frequencies at the time of executing handover to the base station of the different carrier frequency by calling a second base station during a call with the first base station and executing handover through the use of a different spread code in the same carrier frequency.

A moving station synchronously obtains spread codes and frames for the down synchronous channels f1 and c3 of the base station B during the call with the base station A. The moving station measures reception levels of the base stations A and B after it is synchronized with the base station B and measures a timing difference. When the reception level (b) of the base station B is larger than the reception level (a) of the base station A, a handover request is given to the base station A and information on the timing difference is also reported to the base station A at that time. When the reception level (b) of the base station B is smaller than the reception level (a) of the base station A, communication with the base station A is continued.