Disc cartridge adaptor

A disc cartridge adaptor for housing a disc and a disc holder holding at least part of the disc, the disc holder being removably housed in a disc cartridge case, the disc cartridge adaptor comprising:

• a case body including
• a housing portion for rotatably housing the disc, the housing portion being able to house the disc together with the disc holder or without the disc holder
• an exposing portion for exposing at least part of a recording surface of the housed disc, and
• an opening communicating with the housing portion for allowing insertion and removal of the disc holder and the disc;
• and
• a lid pivotably supported by the case body, the lid being able to block the opening,
• wherein the lid includes disc positioning means having a positioning member movable between a first position and a second position with respect to the lid, and
• the positioning member is in the first position restricting the position of the disc within a predetermined range when the disc is housed in the housing portion without the disc holder, and retreats to the second position when the disc holder is housed in the housing portion.