Remote control data is securely transmitted to a device under control. A remote control device transmits an acknowledge request for A ch to the device under control (S21). When the device under control has assigned A ch as the reception channel, acknowledge ACK is received. A ch is assigned as the transmission channel (S23), and a command frame is transmitted through A ch (S24). When acknowledge ACK has not been received, an acknowledge request for B ch is transmitted to the device under control (S25). When the device under control has assigned B ch as the reception channel, acknowledge ACK is received. B ch is assigned as the transmission channel (S27), and a command frame is transmitted through B ch (S28). The remote control device can transmits a command through a channel through which the device under control can receive the command, so that secure remote control can be accomplished.