A turning mechanism is equipped with a wire (first movable member) which moves in a movable direction (direction of the arrow B) under the motive power of a turning actuator, a wire (second movable member) which moves in a movable direction under the motive power of a turning actuator, and a coupler connecting the two wires. The coupler is configured in a manner so that the wires are capable of being moved independently in the case that a difference (differential angle) between the toe angles of the rear wheels lies within an allowable range, whereas in the case that the differential angle has exceeded the allowable range, is configured in a manner so that the wires are capable of being operated in a mutually interlocked manner.