Charged particle beam treatment apparatus

A charged particle beam treatment apparatus comprising:

• an accelerator configured to emit a charged particle beam by accelerating a charged particle;
• an irradiation unit configured to irradiate an irradiation target body with the charged particle beam;
• a beam transport line that connects the accelerator and the irradiation unit to each other, and configured to transport the charged particle beam from the accelerator to the irradiation unit;
• and
• a control unit configured to control the irradiation unit in irradiating the irradiation target body with the charged particle beam,
• wherein in a case where the irradiation target body is virtually divided into a plurality of layers in an irradiation depth direction of the charged particle beam, the irradiation unit includes a scanning unit configured to scan each layer with the charged particle beam, and
• wherein after all of one layer is scanned and a first region of the one layer is irradiated with the charged particle beam by using a first current value, the control unit controls the irradiation unit so as to scan all of the one layer and irradiate a second region of the one layer with the charged particle beam by using a second current value which is different from the first current value wherein the control unit controls the irradiation unit so that the second region irradiated with the charged particle beam by using the second current value includes a region different from the first region irradiated with the charged particle beam by using the first current value.