To reduce a communication interrupt time during a speech accompanied by a switching of communication channels.

In the PHS terminal provided with two synthesizers 13a, 13b, when a condition of hand-over holds during communication, the one synthesizer 13a holds the communication channel to continue the communication, and other synthesizer 13b retrieves a surrounding CS, discriminates the communication capability of the CS found-out, establishes synchronization with a common channel of the CS whose communication capability is discriminated to be available for communication, requests the assignment of a new speech channel, confirms the presence of interference of the new communication channel after the reception of assignment, and the speech channel maintained by the one synthesizer 13a is closed and the new speech channel is open to continue the communication, after no interference is conformed.