A control signal generated as a result of the actuation of each of control switches of a control section is multiplexed by a multiplexing section, and the thus multiplexed signal is sent to a multiplex transmission line. Load control sections receive the multiplexed control signal sent over the multiplex transmission line. The load control sections then control the electric power fed to a corresponding one of loads on the basis of the received control signal. Control data, representing the form of output control of the corresponding load which is controlled as a result of the actuation of the control switch, are stored according to the control switches. Control means control the electric power fed to the load on the basis of the control signal using the control data.