In a mobile communication system, radio channel capacity can be secured. A plurality of base stations transmit to a mobile station information X0 and the like about diversity handover, and a reference signal (such as a perch signal). The mobile station measures received quality (such as a received power) of the reference signal. The mobile station makes a decision for each of the plurality of base stations as to whether the service area is to be selected as a candidate of a service area in which the mobile station will start new communication, and/or as a candidate of a service area in which the mobile station will stop current communication.