Patent ID: 6900446

Claim:
A method for irradiating charged particle beam to an irradiation object with a charged particle beam irradiation equipment which comprises: a first scanning electromagnet for scanning a charged particle beam in a first direction, a second scanning electromagnet for scanning a charged particle beam in a second direction intercrossing with said first direction, a first power supply for applying a voltage to said first scanning electromagnet, which comprises a first power supply portion having no filter and a second power supply portion having a filter; and a second power supply for applying a voltage to said second scanning electromagnet, which comprises a third power supply portion having no filter and a fourth power supply portion having a filter; wherein after finishing the irradiation of the charged particle beam to a first irradiation area in the irradiation object, when the irradiation position of the charged particle beam is changed over to a second irradiation area from said first irradiation area in said first direction in the irradiation object while the irradiation of the charged particle beam is being stopped, a voltage, of which absolute value is larger than a voltage applied to the first scanning electromagnet from said second power supply portion that is necessary to keep the irradiation position of the charged particle beam in the first irradiation area, is applied from said first power supply portion to the first scanning electromagnet.