Abstract: a fastened structure comprising: a first member provided with a female screw; a second member provided with an opening; and a male screw fastening the first member and the second member with each other and including a male screw portion, and a head portion having a bearing surface, wherein the male screw portion is threaded in the female screw through the opening of the second member, wherein the second member is provided with a substantially circular folded portion including a curved surface defining the opening and including a free end having an edge pressed against the bearing surface of the male screw.