It becomes possible to monitor a driven state of each wheel in a wheelchair whose wheels are driven according to output information calculated based on input information. A left wheel controller and a right wheel controller are provided. The presence or absence of a drive abnormality of the left wheel is determined by the right wheel controller receiving first drive related information that is related to a drive of the left wheel and transmitted from the left wheel controller, and the presence or absence of a drive abnormality of the left wheel is determined by the left wheel controller receiving second drive related information that is related to a drive of the right wheel and transmitted from the right wheel controller.