There is provided a library device which can be restored to working order quickly and reliably even when a control board containing information necessary for the operation of the library device is replaced. The library device includes a cell array which consists of an array of multiple cells each of which contains one cartridge containing a magnetic tape, magnetic tape drives in which the cartridges are removably mounted and which access the storage medium contained in the cartridges, a robot which transfers the cartridges between the cell array and the magnetic tape drives, a main control board which controls the operation of the entire library device, a barcode label which represents ID information for identification of the library device, and cell flags which are marks used to recognize the locations of the cells composing the cell array.