PURPOSE: To enable to mechanically or continuously pile up undried board after coating, by sending the board in the apparatus one by one piece and laying the slipsheet on the board mechanically or automatically at every time of accumulation.

CONSTITUTION: One piece of the undried rectangular board A is placed after coating the first piece and tip end of the beltlike slipsheet rolled on the slipsheet roll B1 is fixed adjacent to the one end of longish direction and the slipsheet is laid on the board A by drawing out for the other end side of the longish direction of the board A. Next, the above described slipsheet is laid on the second board A by drawing out from the other end side of the longish direction of the board to the one end side, after placing the second board A on the above described laid slipsheet fitting to the first board. After that, drawing direction of the slipsheet is changed in the same way at every time of placing the new board A and the board is piled up putting the slipsheet between each board A successively.