PROBLEM TO BE SOLVED: To protect a disc housed in a cartridge main part and allow the disc to turn stably without producing the surface vibration of the disc. ;SOLUTION: A disc 5 which has a center core 8 which is to be chucked by a rotary driver and can be attached to the rotary driver and turned with a revolution of at least 3000 rpm and a cartridge main part 4 in which the disc 5 is housed are provided. A center opening 25 through which the center core 8 of the disc 5 protrudes out is formed in the center part of the lower surface side of the cartridge main part 4. When the disc 5 is turned, air is supplied from the center opening 25 to produce an air flow between the inside lower surface of the cartridge main part 4 and the disc and the surface vibration of the rotating disc is restricted by the air flow and pressurized air produced between the inside upper surface of the cartridge main part 4 and the disc.;COPYRIGHT: (C)1999,JPO
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