To provide a mobile communication device compatible with a plurality of communication systems capable of reducing the number of base stations in which other communication systems fail in location registration when one communication system is communicating.

After an initial value of a report base station number is set up (step S10), it is judged by a signal from a upper layer unit whether it is in PHS (Personal Handyphone System) communication or not, and it stands by until PHS communication is started (step S11). If PHS communication is reported, a parameter of the report base station number is set to "1" (step S12), and it waits until PHS communication is completed (step S13). When termination of PHS communication is detected by the signal from the upper layer unit, it returns to step 11, after the parameter of the report base station number is reset to the initial value (step S14).