A disc cartridge includes a case accommodating a disc and having an aperture hole formed on a first surface of the case so that a recording/reproducing apparatus access a recording surface of the disc, and an open hole formed on a second surface to be open to an outside of the case, a shutter opening/shutting the aperture hole and installed in the case, a disc holder installed at a side defining the open hole to move up and down and covering a gap between an outer circumference of the disc and an inner surface of the side defining the open hole when the disc holder descends, and a shutter driving mechanism moving the shutter so that the aperture hole is open/shut. Thus, a passage through which dust is introduced toward an information area of the disc, and a gap formed at an outer circumference are blocked by the disc holder so that a possibility of contamination by dust can be reduced.