Corrugated paper carton making device, carton making method and carton making treatment method

The invention provides a carton making device and a carton making method suitable for making small-size corrugated cartons. A carton manufacturing device is provided with: a stocker (1) for holding a plurality of folded original cartons of a corrugated carton having an upper opening and a lower opening, the folded original cartons facing up and down and being stacked; an unfolding unit (20) which is arranged on the upstream side of the conveying direction substantially orthogonal to the overlapping direction of the original box and enables the single side surface of the original box to move from the first side of the stocker side to the second side away from the first side so as to unfold the original box to form an opening in the upper part and the lower part; a folding unit for folding the lower part of the open box expanded at the upstream part in the conveying direction; a transfer unit (40) for feeding the tank from the upstream side to the downstream side in the conveyance direction; a conveyor belt uni