To prevent erroneous receiving of standard radio wave caused by the noise of peripheral devices in an electronic device with a function of a relay device and to easily receive standard radio wave while allowing sent-out relay radio wave to easily reach a desired receiver such as a radio controlled clock.

An air conditioner is provided with an outdoor unit 100 and an indoor unit 200 connected to the outdoor unit 100 through piping 300. The outdoor unit 100 is provided with a receiving antenna for receiving standard radio wave. When receiving the standard radio wave, the operating state (in operation/stand-by) of the air conditioner is first determined, and in the case of standing by, time data extracted from the received standard radio wave is transmitted to the indoor unit 200 through wiring 310 provided along the piping 300. The indoor unit 200 corrects the present time based on the time data received from the outdoor unit 100, and the relay radio wave including the present time data is sent out every fixed time (specifically one minute).