To shorten the tact time and increase the object process quantity in a unit time by stacking the prescribed number of objects with multiple holding means each holding an object respectively.

The first object is sucked and held by the second suction pad 5B, then a robot arm tip is moved, and the first suction pad 5A is moved above the expected holding position of the second object in place of the second suction pad 5B. The suction valve of the second suction pad 5B of this hand is closed, the first object is dropped in a stack 6, the piston rod of the first air cylinder 3A is extended, the suction valve of the first suction pad 5A is closed, and the second object is sucked and held by the first suction pad 5A. The robot arm tip is moved, and the second suction pad 5B is moved above the expected holding position of the third object in place of the first suction pad 5A.