A floppy disk drive includes a frame having a bottom portion and left and right walls and a casing for covering the frame. The casing includes an upper cover for covering an upper side of the frame and a lower cover for covering a lower side of the frame, in which the upper cover has a top plate and left and right side plates, and the lower cover has a bottom plate and left and right plates. Each of the side walls of the frame is designed so as to have size and height that are partially overlapped with the side plate of the upper cover and the side plate of the lower cover, respectively, at each side of the casing, thereby providing a triplex structure for reinforcing each side of the casing.