To improve operation feeling in inserting a disk cartridge into or pulling it out of the holder means.

The characteristic of the device is such that a shutter opener 15 is provided which opens or closes the shutter 61 of a disk cartridge 60 as inserting it into or pulling it out of its holder 11; that the shutter opener 15 is equipped with a first engaging part 15a that can be engaged with the shutter hole 61a and a second engaging part 15b that can be engaged with the end part 63 on the inserting side of the cartridge, and is supported freely rotatably on the holder with the middle of both engaging parts as the fulcrum; that, at the time of inserting the cartridge, the second engaging part 15b is engaged with the end part on the inserting side of the cartridge, with the shutter opener 15 rotating and imparting an engaging force to the cartridge side, and that, at the time of pulling out the cartridge, the engagement is released between the second engaging part 15b and the end part on the inserting side of the cartridge, with the shutter opener 15 rotating in the opposite direction and releasing the pressing force.