A leaf spring bracket is fixed to an outer surface of a vertical wall of a side member in a vehicle transverse direction by use of rivets penetrating the vertical wall. A gusset which couples an end of a cross member in the vehicle transverse direction with the side member has a vertical plate and upper and lower horizontal plates. The vertical plate is fixed to the vertical wall of the side member. The upper and lower horizontal plates extend inward in the vehicle transverse direction from upper and lower ends of the vertical plate, respectively, and are fixed to upper and lower walls of the cross member, respectively. The vertical plate has ribs protruding inward in the vehicle transverse direction. The ribs form and define recessed parts in an outer surface of the vertical plate in the vehicle transverse direction. Parts of the rivets, which project from an inner surface of the vertical wall in the vehicle transverse direction, are housed in the recessed parts. Thus, the vertical plate is fixed in a state of coming into surface contact with the inner surface of the vertical wall in the vehicle transverse direction.