Disk cartridge, and recording and/or reproducing device

A recording and/or playback apparatus, comprising:

• a cartridge mount on which there is mounted a disk cartridge including:
• a disk;
• a cartridge body housing the disk rotatably and having formed therein a write and/read opening through which a part of the disk is exposed to outside;
• a shutter member supported movably on the cartridge body to uncover and cover the write and/read opening;
• a first concavity formed on a side of the cartridge body over which the shutter member slides and in a region opposite to a region where the shutter member is moved, across the write and/or read opening;
• a bent portion formed along one lateral side of the shutter member to close a gap resulted between the shutter member and first concavity when the shutter member has been moved to a position to cover the write and/or read opening;
• and
• a second concavity formed at a part of the first concavity, adjacent to the write and/or read opening and deeper than the first concavity;
• and
• a write and/or read unit provided opposite to the write and/or read opening in the disk cartridge mounted on the cartridge mount to make write and/or read to and/or from the disk.