Provided is a remote control system with which leakage current flowing in a switch can be reduced so that power consumption can be reduced. The remote control system includes a portable information terminal, a server, and an electric device. The on/off of the switch included in the electric device is controlled using information transmitted from the portable information terminal to the server. The switch includes a transistor formed using a semiconductor whose band gap is larger than that of single crystal silicon in a channel formation region.