To reduce returns of defect products and cost by removing the separation of two cups from stacked cups.

A main suction nozzle 7 having a plurality of suction openings at the upper part and the circumferential face is elevated toward the inside of the lowermost cup of the stacked cups to suck the inner face of the bottom of the lowermost cup and also sucks the inside of the circumferential face of the cup equally to pull the circumferential face inward to be a smaller diameter, and the circumferential face of the second cup from the lowermost cup is sucked outward by air sucking from a side face suction block 5 so that the circumferential face of the second cup is not pulled inward together when the circumferential face of the lowermost cup is pulled inward and then the main suction nozzle is lowered to separate only the lowermost cup, the circumferential face of which is stripped from the circumferential face of the second cup, from the lowest part of the stacked cups.