When packing a polycrystalline silicon with a two-layer structured packing body comprising an inner bag (1a) and an outer bag (1b), there are used the inner bag (1a) and the outer bag (1b) having bottom sections (4a, 4b) provided with a pair of tucked sections, the shape of which is substantially a triangle in plan view, formed by inward-folding the portions continued from both of rectangular side face sections (3a, 3b), and when storing the inner bag (1a) that stores the polycrystalline silicon therein into the outer bag (1b), the bottom sections (4a, 4b) are superimposed with the respective tucked sections (6a, 6b) of the inner bag (1a) and the outer bag (1b) displaced from each other by 90° so that they do not overlap on each other.