A basket has a lattice-like section for accommodating individual used nuclear fuel in predetermined positions in a cask. The basket is made from aluminum composite material having good neutron absorption ability, excellent mechanical property and workability. The aluminum composite material is made by having, in an Al or Al alloy base phase, B or B compound with a neutron absorption ability and an additive element, e.g. Zr or Ti, for giving a high strength property, and subjecting to a sintering under pressure.