To attain miniaturization by setting an ID number of a telecontrol device so as to select a communication form thereby eliminating the need for a setting switch.

A microcomputer μC3 has a communication form selection means 3a, a data transmission means 3b, and a data reception means 3c and connects to a serial input output section 4. A telecontrol device 1 is provided with a storage section 11 storing an ID code. Then the input telecontrol device 1 and an output telecontrol device are used to attain 1-1 simplex transmission and an on/off signal is sent in a radio wave. Then a one-way communication form and a two-way communication form are selected depending on the ID code set to each telecontrol device. When there is any idle channel without a carrier, the ID code and the data of the input telecontrol device are sent to the receiver side.