A cask cushioning body includes an end-surface side member (2) in which a plurality of plates (21, 22) made of steel are formed at a distance between plate surfaces of the plates (21, 22) that face each other, and in which the plate surfaces of the plates (21, 22) are arranged along an end surface (100a) of a cask (100), and a circumferential-surface side member (3) that forms a cylindrical body (31) made of steel, one end of which is connected to a periphery of the end-surface side member (2), and that is arranged along an end-portion outer-circumferential surface (100b), wherein an impact absorber (4) that absorbs an impact by deforming is provided outside of the end-surface side member (2) and the circumferential-surface side member (3).