A mobile communication terminal has a function of communicating with two types of base stations, for example, one base station belongs to the Global System for Mobile communications (GSM) and another base station belongs to the Wideband Code Division Multiple Access (WCDMA) system. The mobile communication terminal receives radio signal from a communicating base station and a neighboring base station, and measures received radio signal quality. Then, judging whether hand-over process is to be executed or not based upon comparison of the measured received radio signal quality and relationship between the received radio signal quality and data throughput.