An optical disc device is provided with a tray for mounting a disc or a cartridge thereon, a chassis that is laid out under the tray, and a top plate that is laid out above the tray. The optical disc device comprises two types of holding mechanisms that form either a single disc mounting space or a cartridge mounting space according to a shape of a single disc or a cartridge to be mounted in the tray, and hold the single disc or the cartridge in the respective mounting space.