The disc changer device, for transporting a tray to a stand-by position where trays are housed in a stacked state, to a disc exchange position where a disc on the tray is exchanged, as well as to a disc recording/reproducing position where a recording/reproducing operation is carried out on the disc on the selected tray, is provided with a plurality of tray locking units that are prepared in association with the respective trays, and engaged with a corresponding trays so that each of the corresponding trays is prevented from being transported from the stand-by position to the disc exchange position, and an engagement releasing unit for releasing engagement between the selected tray and the tray locking unit related to the selected tray as well as engagement between a tray adjacent to the selected tray on a lower side thereof and the tray locking unit related to the adjacent tray.