PROBLEM TO BE SOLVED: To provide a neutron capture therapy device capable of suppressing both occurrence of blistering in a target and damage to the target.SOLUTION: A neutron capture therapy device 1 comprises: a plate-like target 8 that generates a neutron beam N in response to irradiation of a charged particle beam L and a cooling plate 18 that includes a cooling-medium flowing spiral groove 24 arranged in a state of contacting the target, and the target 8 protrudes along an irradiation axis A of the charged particle beam L. Since the plate-like target 8 protrudes along the irradiation axis A of the charged particle beam L, structural strength of the target 8 is enhanced. Therefore, it is possible to reduce plate thickness D1 of the target 8 enough to suppress occurrence of blistering while suppressing damage caused to the target 8 by heat, water pressure or the like.
