it is an object of the present invention to provide a focused ion beam apparatus capable of prolonging a service life of an aperture , preventing contaminants from increasing when a column valve is closed , and being quickly restarted . a high - voltage power supply controller lowers an extraction voltage applied to an extraction electrode or lowers a control voltage applied to a control electrode to set an emission to 0 μa when a column valve is closed . the high - voltage power supply controller returns the extraction voltage applied to the extraction electrode to an original extraction voltage or returns the control voltage applied to the control electrode to an original control voltage when a column valve is opened .