A library apparatus comprises a plurality of cartridges each containing a recording medium, a storage rack in which the plurality of cartridges is stored, at least one drive that records or reproduces data in or from the cartridge, and an accessor that holds the cartridge and transports the cartridge between the storage rack and the drive. Herein, a hand mechanism included in the accessor includes a buffer mechanism that, even if the advancement of the hand mechanism is stopped with the hand mechanism abutted against the cartridge within a predetermined range before reaching a normal position, allows the hand mechanism to hold the cartridge. The buffer mechanism is incorporated in a rotary base included in a crank mechanism. When external force is applied to a crank arm, the buffer mechanism moves a rotary shaft of the crank arm. Consequently, even if the hand mechanism approaches the cartridge storage rack too closely, the hand mechanism can access the cartridge without the necessity of retrying the advancement.