PURPOSE: To correctly determine a steering position by generating a signal related to motion of a steering mechanism from a signal generating device, and forming a signal to express a position of the steering mechanism by a processor based on the output signal.

CONSTITUTION: In a mechanism in which a steering device is controlled by a command formed by a control module including a processor receiving input of an output signal of a steering sensor 20 or the like, the steering sensor 20 is composed of a shutter wheel 30 installed on a steering shaft 38, and detectors A, B disposed at an interval having the wheel 36 between each other. Each detector A, B is composed of a light emitting diode 42, and a photodiode 44, and a signal to motion of the steering mechanism is outputted from the photodiode 44. In the processor, above sensor signal is outputted as a signal to express a steering position.