A boron neutron capture therapy system has a neutron beam irradiation device, a patient restraint/placement portion, a three-dimensional diagnostic device, an irradiation table, a position adjustment mechanism, and a control unit. The boron neutron capture therapy system performs position determination with a sufficient degree of accuracy at the time of the boron neutron capture therapy. Further, the control unit, using the movement of the irradiation table, performs collision avoidance processing that changes the movement of the irradiation table before the patient restrained on the patient restraint/placement portion receives injury by colliding with the irradiation port, and thus, collision between the patient and the irradiation port can be avoided.
