A disk-storage device comprising a conveying mechanism having a plurality of clutching sections for clutching cartridges; a plurality of recording/reproducing units for recording and reproducing information on and from disks in the cartridges; and a plurality of lodging shelves for lodging cartridges. The number of recording/reproducing units and of lodging shelves is the same as the number of clutching sections, these three categories of components being arranged in the same positional relationship. They are all contained in a case having cartridge-supply/discharge openings through which cartridges are put into and taken out of the device. To enable a plurality of cartridges to be simultaneously held by the clutching sections of the conveying mechanism, a plurality of loading mechanisms temporarily hold cartridges, adjusting their positions accordingly. The cartridge-supply/discharge openings and the loading mechanisms are arranged in the same positional relationship. The device further comprises a divisional recording means adapted to time-divide information from the exterior and to distribute the information thus divided to the recording/reproducing units so as to record it on the disks in the cartridges, and a synthetic reproduction means adapted to synthesize information recorded on the disks by the recording/reproducing units in predetermined equal periods and to transmit it to the exterior.