A recording disk cartridge includes a plurality of flexible recording disk media, a rotational member, and a cartridge case. The rotational member holds the recording disk media so that the recording disk media simultaneously rotate. The cartridge case provides a rotationally free housing for the recording disk media and the rotational member. The cartridge case has an opening to allow an end portion of the rotational member to be exposed to an outside of the cartridge case. The recording disk cartridge has an elastic member which provides a force to thrust the rotational member toward the opening.