To easily shift and store a heavy object in a place provided with no cargo loading/unloading equipment or by means of a truck by dispensing with a transferring work, which deteriorates workability in a conventional heavy object shifting method, from a conveying vehicle to a workbench used in machining.

In hooking work, a required plural number of liftable workbenches with wheels necessary for work and a single workbench lifter, which is operated by an electric motor or an elevating cylinder and provided with an elevating mechanism having rolling wheels, are arranged and used in combination with each other, and a plurality of workbenches can be shifted and moved upward/downward by means of the single lifter, so that workability can be improved and storage can be simplified.