There are provided: a container body (11) that has an opening in one end; a lid member (12A) that seals the opening; a prismatic pipe (30) that is arranged in the container body (11); a fuel holder (20) that covers a side surface of a fuel assembly when inserted into the prismatic pipe (30); and pressing members (37a, 37b) that are arranged on the prismatic pipe (30) and press the fuel holder (20), in the prismatic pipe (30), against inner surfaces of the prismatic pipe (30). One end (23) of the fuel holder (20) is formed in a tapered shape inclining toward an inside of the fuel holder (20). One end of the prismatic pipe (30) is provided with a first guide member (40) that has a recess (41) conforming to a shape of the one end (23) of the fuel holder (20).