Abstract: A communication device includes a first terminal unit connected to an actuator device having a sensor. Transmission of a steering signal transmitted from a steering wireless device to the actuator device, and transmission of detected signal detected by the sensor in the actuator device are conducted via the first terminal unit. The communication device further includes a control unit. The control unit conducts processing to generate a connection error signal representing that the actuator device are not connected on the basis of a result of determination whether the detected signal is acquired from the actuator device via the first terminal unit, and transmit the connection error signal to the steering wireless device side.