Abstract: To obtain a neutron detector capable of measuring high dose neutrons with high neutron/gamma-ray discrimination ability and high efficiency. A scintillator 10 has a layered structure in which a phosphor layer 11 and a light transmission layer 12 are alternatelylaminatedin z direction. The phosphor layer 11 is made of a phosphor material emitting fluorescent light by absorbing neutrons, the material being, for example, a scintillator material used in neutron detectors having alreadybeen known. The light transmission layer 12 is made of a material highly transmitting fluorescent light emitted by the phosphor materialand only slightlyabsorbingneutrons. In the scintillator 10, when neutrons and gamma-ray photons enter it, luminescence intensity (pulse height) due to neutrons is significantly different from that due to gamma-ray photons. It makes it easy to discriminate between outputs due to the two kinds of radiations.