To provide a remote commander control system in which a remote commander surely controls a controlled device even when the direction of the controlled device controlled by the remote commander differs or a distance between the remote commander and the controlled device is too far.

A relay device 2 is provided between a remote commander 1 and a liquid crystal projector 3 at the front side of which a reception section 3a is provided, the relay device 2 receives a control signal S1 sent from the remote commander 1 and sends the signal again toward the liquid crystal projector 3 as a control signal S2. Thus, the liquid crystal projector which has not been controlled from its rear side is made controllable even from the rear side. In the remote commander 1, a control signal entered from an entry section 1a is received by a control section 1b and a transmission section 1c sends the control signal S1 by means of an infrared ray or the like. A reception section 2a of the relay device 2 receives the control signal S1 and a retransmission section 2c sends the control signal S1 again as the control signal S2.