A thickened part is formed in the first member. The thickened part has a protruded part that is convex on one side in the thickness direction of the first member, so that the thick portion is set thicker than the general portion as the other portion. At least a part of the second member overlaps a part of the first member that includes the thickened part from another side of the first member in the plate thickness direction, and the self-piercing rivet is driven into a fastening overlapped part that is a part that the second member overlaps the thickened part from a second member side, so as to fasten the first member and the second member.