PURPOSE: To transfer one batch (corrugated cardboard) in the upper portion to a supply conveyor easily and assuredly by providing a transfer auxiliary mechanism adapted to lift one batch separately from the other batches on a pallet to clearly separate the part to be transferred.

CONSTITUTION: When the ascent of a horizontal fork 3 forces the uppermost corrugated cardboard piece 2 to get to a stop position for a top surface, a switch is operated to stop the ascent of the horizontal fork 3. Then, the upper part (required number) of the first batch of corrugated cardboards 2 facing a supply conveyor, is pushed toward a transfer auxiliary mechanism 5, and the side portion of the upper corrugated cardboard 2 is brought on a transport conveyor 6 and an inverting arm 7, simultaneously a contact plate 43 being pressed against the side portion of the upper corrugated cardboard 2, and a limit switch LS1 is operated to drive an elevating mechanism of the transfer conveyor and the like, so that the top surfaces of the transfer conveyor 6 and the inverting arm 7 are lifted up to a transfer level. After this, if an invertion is not involved, only the transport conveyor 6 is driven to transfer the corrugated cardboard 2 onto a supply conveyor 4.