[PROBLEMS] To efficiently switch frequencies of communication between a mobile station and a base station.[MEANS FOR SOLVING PROBLEMS] There are included a mobile station (B6) that switches frequencies between base stations (B1-B5) to perform communication; and a base station control apparatus (B7) that controls the base stations and the mobile station (B6). The mobile station (B6) has a level measuring part (A7) that measures the communication quality information, while the base station control apparatus (B7) has a control part (F3) that performs, based on the foregoing quality information, a determination as to the foregoing frequency switching. This determination as to the foregoing frequency switching is performed based on the communication quality information measured by the mobile station (B6) that switches frequencies between the base stations to perform communication. The determination as to the foregoing frequency switching is performed by either the mobile station (B6) or the base station control apparatus (B7). This can improve the stability of the communication quality and further reduce the activations of unnecessary monitoring of different frequencies.