An object of the present invention is to provide a charged particle beam apparatus that effectively removes electrical charges from an electrostatic chuck.In order to achieve the above object, the charged particle beam apparatus of the present invention includes a sample chamber that maintains a space containing an electrostatic chuck mechanism (5) in a vacuum state; and in which the charged particle beam apparatus includes an ultraviolet light source (6) to irradiate ultraviolet light within the sample chamber, and a irradiation target member irradiated by the ultraviolet light; and the irradiation target member is placed perpendicular to the adsorption surface of the electrostatic chuck.