A suspension device for suspension of an axle by an intermediate portion of a single leaf spring has first restriction device which restricts, upon breakage of the leaf spring at a position behind the intermediate portion of the spring, the rear portion of the leaf spring from tilting downwardly relative to a shackle, and a second restriction device for restriction of the shackle from pivotally moving backward beyond a predetermined angle. The first restriction device is constituted by a stopper plate on the shackle for support of the rear portion of the leaf spring from below upon breakage.