To enable a caller to record a message into a moving set immediately when the moving set side moves out of a communication enable zone.

A master set 1 is provided with a level detecting part 8 which detects the strength of a radio wave transmitted from a slave set, and outputs a level deterioration signal when the strength of the detected radio wave is lower than a prescribed level, a message transmitting part 13 which transmits a guide message for reporting that communication with the salve set is made invalid, and urging transmission of a recording message when the level deterioration signal is outputted, and a message storing part 12 which stores the recording message introduced through an outside circuit 2. The recording in message stored in the message storing part 12 can be reproduced.