Patent Number: 
Section: abstract

The invention provides a charged particle irradiation apparatus including: a collimator apparatus provided in an irradiation nozzle that emits a charged particle beam to an irradiation target; and a collimator control unit that controls the collimator apparatus. The collimator apparatus includes a collimator mechanism having one or more arm-shape collimators extending from a base part and a drive mechanism that moves the collimator mechanism on a plane perpendicular to a traveling direction of a charged particle beam. The arm-shape collimator includes one or more movable leaves that rotate independently of each other on the perpendicular plane. By moving the collimator mechanism and/or rotating the movable leaves so that the arm-shape collimators are arranged along a shape of an edge of an irradiation target on the perpendicular plane, the collimator control unit causes the arm-shape collimators to block a charged particle beam that would otherwise irradiate outside of the edge of the irradiation target.