PURPOSE: To secure high reliability and remarkably reduce the cost by making a constitution in which a floor rack conveyor is driven by motive power from a conveyor drive motor mounted at a stacker crane, and the carrying in or out of a work within the floor rack is conducted.

CONSTITUTION: When a work 12 within a floor rack 1 is carried in or out, a stacker crane 4 ascends/descends by traveling to a warehousing shelf/carrying out shelf, and a motive power transmission device 8 on the crane 4 is connected to a motive power receiver 3 on the rack (1) side, and a floor rack conveyor 2 is driven by motive power from a conveyor drive motor 5 mounted on the crane, and the carrying in or out of the work 12 is conducted. As a result, the need of, as previously, equipping a drive motor at every conveyor 2 of the rack 1 or making a rack a free floor rack, is gotten rid of, so reliability is remarkably improved, and at the same time drastic cost cut can be realized.