Disc cartridge, and information recording reproducing device using the disc cartridge

An information recording/reproducing device for at least one of recording information on and reproducing information from a disc-like recording medium housed in the disc cartridge, with the disc cartridge comprising a case main body having a housing part for housing the recording medium, an aperture that allows a light beam to enter from an optical pickup that is provided to at least one principle plane of the case main body, a thin bridge part provided to the aperture, which is thinner than a cartridge case, and a shutter for opening and closing the aperture, wherein the thin bridge part is disposed at a position farther from the optical pickup than a surface of the recording medium which is on a state in which the disc cartridge is mounted to an information recording/reproducing device, the information recording/reproducing device comprising:

• a turntable for rotating the recording medium;
• an optical pickup that emits a light beam to the recording medium so as to at least one of record and reproduce the information, and which moves to/retracts from the aperture of the disc cartridge;
• and
• a mechanism for moving the optical pickup in an in-plane direction of the recording medium,
• wherein in at least one of a case where the recording medium is to be mounted to the turntable, and a case where the recording medium is to be removed from the turntable, the optical pickup is retracted into a position opposite to the thin bridge part of the disc cartridge.