PROBLEM TO BE SOLVED: To provide a neutron ray detection device capable of suppressing disturbance of a neutron field.SOLUTION: A neutron ray detection device comprises: a scintillator 13 which radiates light caused by incidence of neutron rays； an optical fiber 14 in which the scintillator 13 is disposed on a tip end 14b of one end 14a thereof and which transmits the light radiated by the scintillator 13； and a ferrule 17 which is provided on an outer periphery of the one end 14a of the optical fiber 14 and contains aluminum. Since the aluminum has a property of hardly reacting with the neutron rays in comparison with other metals such as an SUS used as a material of a conventional ferrule, disturbance of a neutron field can be suppressed.SELECTED DRAWING: Figure 3
