To provide a plurality of magazines very closely by saving the space for forming the moving path that is required for allowing a cartridge transporting device to move. A movable magazine that is capable of moving in the lateral direction individually is provided between a first fixed magazine and a second fixed magazine located on both sides. The movable magazine is moved from the position of a cartridge loading/unloading face that corresponds to a cell to which a cartridge as a mount target for a magnetic tape drive is being housed or a cell to which a cartridge that is unmounted from the magnetic tape drive is to be housed so as to form a longitudinal moving path for allowing the cartridge transporting device to move between the magazines neighboring to each other.