Disc cartridge

A disc cartridge comprising:

• a cartridge body having a thickness and an aperture for exposing at least a part of a signal recording area of a disc accommodated therein;
• a shutter slidably mounted on said cartridge body for opening and closing said aperture, the shutter being slidable in a recess formed in a pair of opposing, parallel, lateral faces of the cartridge body;
• a shutter opening groove formed in a first lateral side of said cartridge body and extending along a sliding direction of said shutter which is parallel to the direction of insertion of the disc cartridge into a recording and/or reproducing apparatus;
• a mistaken insertion inhibiting groove formed in a second lateral side of said cartridge body and extending parallel to said shutter opening groove, and said mistaken insertion inhibiting groove being shorter in length than the length of said shutter opening groove;
• wherein said shutter opening groove and the mistaken insertion inhibiting groove are both opened on a third lateral side of said cartridge body which is a leading lateral side in the direction of insertion of the disc cartridge into the recording and/or reproducing apparatus;
• and
• wherein the length (G) of the mistaken insertion inhibiting groove and a length (F) along the direction of the shutter opening groove to a leading edge of the shutter when the shutter is in an open position are taken in directions parallel to the shutter sliding direction and the length (G) of the mistaken insertion inhibiting groove is less than the length (F) along the direction of the shutter opening groove to the leading edge of the shutter when the shutter is in the open position.