To reduce a dynamic load applied to a part welded to an axle housing of a spring bracket, so that the initial condition can be maintained over a long period.

A spring bracket shape is formed in a manner wherein relating to a welding width Do in the axle direction of a lower end member of this spring bracket, a width D1 in the vicinity of a stress bending shaft of this member is made narrower than the welding width D0, the lower end member of this spring bracket is welded to an axle housing, so as to hold a leaf spring, connecting between a body and the axle housing, in a side of the axle housing. In this way, lightening of weight can be attained.