Recording disk cartridge

A recording disk cartridge having recording disk media and a cartridge case for housing the recording disk media, the cartridge comprising:

• a center core for supporting said recording disk media;
• a base frame comprising a side opening that makes said recording disk media front outside, said base frame substantially surrounding a radial directional outside of said recording disk media and configuring a sidewall of said cartridge case;
• a lower plate disposed below said recording disk media and for configuring a lower wall of said cartridge case, wherein a chucked center-hole is formed in order to couple a spindle of a disk drive with said recording disk media;
• an upper plate disposed above said recording disk media and for configuring an upper wall of said cartridge case;
• a rotary shutter for opening and closing said side opening by rotating within said cartridge case;
• and
• a swing shutter disposed between said recording disk media and said lower plate and engaged in said rotary shutter, for swinging in response to a rotational movement of said rotary shutter, and for opening and closing said chucked center hole,
• wherein said center core comprises a separation support portion for supporting said recording disk media in a state of being separated from upper and lower ends of the center core, is pushed up when said swing shutter is closed, and said upper and lower ends are supported by said upper plate and said shutter member.