A disc cartridge is provided. The disc cartridge includes an optical disc
and a main cartridge body unit rotatably housing the optical disc. A
lateral surface of the main cartridge body unit as an inserting end of
the main cartridge body unit into the recording and/or reproducing
apparatus is a semicircular arcuate section having the center of the
optical disc accommodated in the main cartridge body unit as center. The
direction of insertion of the main cartridge body unit into the recording
and/or reproducing apparatus may be discriminated readily to achieve
smooth loading.