An apparatus structure includes a pair of side plates facing each other, and a stay fastened to the pair of side plates with a first screw and a second screw. One of the pair of side plates and a first stay portion of the stay has a first screw hole through which the first screw is inserted. The other has a first internal thread into which the first screw is threaded. One of the pair of side plates or a second stay portion of the stay has a second screw hole through which the second screw is inserted. The other has a second internal thread into which the second screw is threaded. One of the first screw hole or the second screw hole is larger than the other.