Solving Means: A front swinging shaft and a rear swinging shaft (85)respectively as a spindle extended in a longitudinal direction of the body are attached to a body frame(16), right and left suspension arms (72, 71) are mutually independently attached to the front swinging shaft and the rear swinging shaft (85) so that the suspension arms can be vertically swung, and the front swinging shaft and the rear swinging shaft (85) function as a swinging shaft for swinging the body frame (16).
Effect: In the invention, the rear wheels can be independently vertically moved without lateral interference, compared with a case that right and left rear wheels are coupled via a shaft for example, the followability of the right and left rear wheels after a road is increased, the roll of the body can be reduced and the ride comfort can be enhanced. As the right and left suspension arms are attached to the same spindle, the number of parts canbe reduced and further, as the spindle also functions as the swinging shaft, the cost can be more reduced.