PURPOSE: To transmit a signal in a wireless state, to reduce the power consumption of a transmitter/receiver and further to improve the sense of use of the transmitter/receiver by outputting the signal from a conductive member exposed to the outside and transmitting it through a human body to a second conductive member installed at the receiver.

CONSTITUTION: At a transmitter 1, an LED is not driven on the final stage but the output of an amplifier circuit 3 is supplied to an electrode 4. In this case, the output of the amplifier circuit 3 is connected through a capacitor to the electrode 4 and disconnected in the manner of DC. On the other hand, the output level of the electrode 4 is set so as to be lower than weak power regulated by the Radio Wave Act., when the human body touches it. On the reception side, the input circuit of a high impedance is provided inside a selecting circuit 7 in place of a pin diode, and an electrode 6 is connected similarly to the transmitter 1. Then, the signal is transmitted by touching the electrode 4 on the side of the transmitter 1 and the electrode 6 on the side of a receiver 5 with a body (both the hands) 10.