A rear suspension spring support structure enables a rear side member to have an improved rigidity, and thus driving stability is improved. The rear suspension spring support structure has a rear cross member connected to a rear side member with a rear cross member extension being interposed therebetween. An extending portion, on a vehicle lateral side, of the rear cross member extension passes under the rear side member and extends to the vehicle lateral side of the rear side member. The extending portion is welded to a lower surface of the rear side member and a side surface of the vehicle lateral side. A coil spring bracket for receiving an upper end portion of the coil spring is joined to a lower surface of the rear cross member extension.