PURPOSE: To freely set the length of the connection pieces according to the hill interval of the crop plants at no cost of their dense aggregation. CONSTITUTION: Pots 1 formed by expanding a paper sheet or paper-like thin film are connected with connection pieces to form an aggregate pots 3 and the aggregate is alternately turned every a certain length to give a continuously aggregated pots for transplantation. In the aggregate pots, the connection piece comprises the flat part 5 having the equal length to the width of the one side face of the individual pot and the folded part having extended part equal to or longer than the flat part where the longer part is folded. Further, in the folded parts, the folded pieces are adhered to each other with a water-soluble adhesive, and stuck to the side faces of the front and back pots. Then, the alternately turned aggregate pots 3 are bonded to each other by sticking the upper face of the folded part 6 to the side face of the adjacent pot 1 with a water-soluble adhesive so that these adhesion parts may be separated from each other by watering for growing and the pots may be continuously taken out in series from one end.