To enhance assembly and maintenance of a rear wheel suspension. Rear wheel axles extend to the left and right from a final case supported on a rear portion of a vehicle body frame, and rear wheels are independently suspended from left and right portions of a vehicle body. On the left and right sides of the final case, the rear wheel axles are connected to a left-side joint and a right-side joint, and the left-side joint is detachably attached to a side surface of the final case by a separate holder fitted with a driven sprocket meshed with a chain. A joint portion shaft of the right-side joint is borne on the final case through a bearing, a brake disk is attached thereto, and the joint portion shafts are spline connected. In assembling or disassembling, the separate holder can be attached and detached through petal-like cutouts formed in the driven sprocket.