The present invention provides a structure for omitting washers to reduce the number of parts, and keeping the fitting of two members fastened together even when the washers are omitted. The structure includes: a first member having a first screw hole; a second member facing the first member, having a second screw hole larger than the first screw hole, and threaded in a direction opposite to the first screw hole; and a fastener. The fastener includes, along a longitudinal direction: a first screw section having a diameter corresponding to the first screw hole; a second screw section between the first member and the second member, having a diameter corresponding to the second screw hole, and threaded in a direction opposite to the first screw section; a neck at least partially located in the second screw hole; and a head larger in the longitudinal direction than the second screw hole.