This invention is equipped with: a steering shaft provided to an underframe of a carbody of a vehicle travelling on a traveling road surface of tracks; king pins provided as a pair to end sections of the steering shaft at both sides in the width direction; axle hubs swingably provided to the steering shaft via the king pins; tires mounted plurally to each of the axle hubs; guide wheels, which roll over guide rails provided to the tracks in the direction of extension of the tracks, and which are guided from the width direction of the tracks; a guide device part for supporting the guide wheels and the steering shaft; and a steering mechanism for causing the axle hubs to turn about the king pins in accordance with the displacement of the guide device part.