PURPOSE: To simplify structure of a rear wheel steering device, to reduce a cost, and to improve reliability by a method wherein a slider is moved through a link rod along a guide plate by means of a swing arm, and the guide plate is revolved.

CONSTITUTION: When rear wheels 2 are steered, for example, in an iso-phase with rear wheels 16, a swing arm 13 is revolved either leftward or rightward with the aid of a motor 12. A link rod 11 is moved in the same direction as that of the swing arm 13 by means of a guide screen 14 on the swing arm 13 and a slider 10 is slid along a guide groove 6 to vary an engaging position. With this state, the link rod 11 is axially moved through revolution of a guide plate 5 occasioned by steering of the front wheels 16 and a T-shaped arm 8 is revolved. This constitution pulls the one of cables 9a and 9b and switches a hydraulic switching valve 4 of a power cylinder 3 by which the rear wheels 2 are steered.