A neutron capture therapy system includes a therapy table on which an irradiation target is placed, a neutron beam irradiation unit which irradiates the irradiation target placed on the therapy table with a neutron beam, a position measurement unit which measures a position of the irradiation target placed on the therapy table, and a radiation dose distribution output unit which outputs a radiation dose distribution of a neutron beam used for irradiating the irradiation target, based on an amount of positional misalignment of the position of the irradiation target measured by the position measurement unit.
