Charged particle irradiation apparatus

A charged particle irradiation apparatus that performs a scan with a charged particle beam to irradiate an irradiation target spot by spot, the charged particle irradiation apparatus comprising:

• a collimator apparatus provided in an irradiation nozzle that emits the charged particle beam to the irradiation target;
• and
• a collimator control unit that controls the collimator apparatus,
• wherein the collimator apparatus comprises
• a collimator mechanism comprising one or more arm-shape collimators extending from a base part, and
• a drive mechanism that moves the collimator mechanism on a plane (YZ plane) perpendicular to a traveling direction (X-axis direction) of the charged particle beam,
• wherein each of the arm-shape collimators comprises a plurality of movable leaves that rotate independently of each other on the perpendicular plane (YZ plane), and
• wherein by moving the collimator mechanism and/or rotating the movable leaves so that the one or more arm-shape collimators are arranged along a shape of an edge of the irradiation target on the perpendicular plane (YZ plane), the collimator control unit causes the one or more arm-shape collimators to block the charged particle beam that would otherwise irradiate outside of the edge of the irradiation target.