A rotatable grip (ancillary operation member) is provided on a part of a steering wheel body of a steering wheel (main operation member) for turning wheels. When the grip is rotated, a difference is generated between left and right wheels, and a yaw moment generated with this difference can assist or suppress the turning of a vehicle. Because the grip constitutes a part of the steering wheel body, it is possible to rotate the grip to assist or suppress the turning of the vehicle, while operating the steering wheel to turn the vehicle. Because both the steering wheel body and the grip can be operated by the same hand of a driver, operational burden on the driver is alleviated. Thus, it is possible to concurrently provide an excellent operability of the main operation member for controlling a kinetic state of the vehicle, and an excellent operability of the ancillary operation member for controlling the operation of a yaw moment generating device.
