PURPOSE: To improve a working efficiency by matching a level of an upper surface in which a buffer member and a slide sheet are laid to that of a lower surface of a crude base plate on a shelf plate, sliding the base plate to the shelf plate side, and transferring the base plate to the shelf plate while sliding the member on the shelf plate.

CONSTITUTION: A lifter B is moved to rise a special-purpose pallet C thereby to match a level of the surface of the pallet C to that of the surface of a slide sheet M. Then, a crude base plate X is slid from the pallet C and so moved that part of the front end of the plate X is placed on the sheet M above the end of a cushion member S. The plate X is pressed in the state that only its front end remains placed on the sheet M, the cushion member suspended from the front edge of a shelf plate D, is lifted, elongated on the plate D, and the sheet M is extended from the other side of the plate D. And, when the sheet M is pulled, it is extracted between the cushion member and the plate X to entirely transfer the plate X to the plate D.