It is an object of the present invention to provide a disk storage apparatus which employs a rotary actuator mechanically excellent as compared with a linear-movement actuator and can employ, in a disk cartridge, a slidable shutter that easily prevents dusts from entering the disk cartridge, and a disk cartridge therefor. The disk storage apparatus includes a disk cartridge in which a disk-like storage medium is rotatably accommodated, an apparatus body onto which the disk cartridge is detachably loaded, a shutter opening and closing mechanism provided on the apparatus body for, in an interlocking operation with an operation of attaching and detaching the disk cartridge, opening and closing a shutter capable of opening and closing a head-positioning-mechanism insertion slot of the disk cartridge, and a rotary head-positioning mechanism provided on the apparatus body for inserting a head portion for recording and/or reproducing information on and/or from the disk-like storage medium through the head-positioning-mechanism insertion slot opened when the disk cartridge is loaded,. The disk cartridge includes a slidable shutter for opening and closing the head-positioning-mechanism insertion slot by its sliding operation. The rotary head-positioning mechanism includes a rotation actuator for inserting the head unit into the disk cartridge through the head-positioning-mechanism insertion slot. According to the disk storage apparatus, it is possible to provide the disk storage apparatus which makes it difficult for the dusts to enter the disk cartridge and has a high reliability in the recording and/or reproduction.