A disk cartridge includes a case accommodating a disk and having a first hole, a cover installed at the case and having a second hole open to an outside of the cover, a shutter installed to be capable of moving with respect to the case disposed under the disk to open/shut the first hole formed on the case, and a plurality of protruding portions provided at the shutter to support a non information area provided at an outer circumferential side of the disk and having inclined surfaces inclined at a predetermined angle. When the shutter is opened, the disk descends along the inclined surfaces. When the shutter is shut, the disk ascends along the inclined surfaces to closely contact a portion of the cover disposed around the second hole of the cover. Thus, since the shutter contacts only a non-information area of the disk, an information area of the disk can be safely kept from being damaged during an operation of opening/shutting the first hole. Also, since an edge portion of the outer circumferential side of the disk closely contacts a sealing member disposed around the second hole of the cover in a state that the shutter is shut, a gap through which dust can intrude is blocked, so that contamination of the recording surface can be reduced.