CHARGED PARTICLE GUN AND CHARGED PARTICLE BEAM DEVICE

The present invention provides a charged particle gun including: a charged particle source (1); an extraction electrode (2); an opening (14) through which a charged particle beam passes; and a barrier provided in an area defined by connecting the charged particle source to the opening, the barrier serving to prevent molecules existing in a downstream vacuum chamber from passing through the opening to adsorb onto the charged particle source. Accordingly, the molecules existing in the downstream lower-vacuum chamber can be prevented from adsorbing onto the charged particle source, so that current noise can be reduced. This enables stable operations of the charged particle beam gun and a charged particle beam device including the charged particle beam gun.