PURPOSE: To prevent production of crosstalk to other equipment and to save power consumption by providing a signal processing circuit stopping the repeating transmission of a wireless signal when a demodulation signal added with a specific transmission code is inputted to each repeater.

CONSTITUTION: Upon the receipt of a demodulation signal from a reception circuit section 1b, a signal processing circuit 1a revises and ID code and a transmission code added to a control data only according to a rule and generates a transmission signal in which the transmission code is added to the original ID code and control data. Then a switching signal is sent to a transmission reception switching circuit 1d to select the state into the transmission state and the transmission signal generated in a transmission circuit section 1c is outputted to repeatedly transmit a wireless signal. When a demodulation signal added with a specific transmission code is inputted to the signal processing circuit 1a, however, the relay transmission of the wireless signal is stopped. Since the consecutive relay transmission between repeaters A1, B1 is prevented, the radiation of an undesired radio wave is reduced.