When a radio unit incorporated in a facsimile device is made replaceable to make various radio units usable, a change in specification of communication between a facsimile body and a radio unit is made unnecessary. For this purpose, according to the present invention, a radio unit, which is united, for performing radio communication with another communication device, a controller for controlling the communication device, and an interface for performing communication of various control signals between the radio unit and the controller are arranged, the radio unit is replaced with another type of radio unit, and the interface and the control signal transmitting/receiving through the interface are shared regardless of the type of radio unit.