Power is taken out from radio waves through an antenna and a power receiving unit. A signal receiver, a comparator, and an ID signal holder are operated with the taken-out power to compare an ID contained in a received signal with an ID read out from the ID signal holder. When both the ID's are matched with each other, a switch for a main power source is turned on. In trying to remotely operate household electrical appliances by utilizing the Internet that has become increasingly popular, standby power is consumed if the electrical appliances are kept in a standby state at all times. Since power is taken out from radio waves, the invention is able to cut the standby power in an environment where the radio waves are transferred via radio communication that is expected to be more and more prevalent in future.