CHARGED-PARTICLE GUN AND CHARGED-PARTICLE BEAM DEVICE

PROBLEM TO BE SOLVED: To allow a charged particle beam device to stably operate by stabilizing primary charged particles ejected from a charged particle source for a long time.SOLUTION: There is provided a charged-particle gun which includes a charged-particle source and a lead-out electrode leading a charged-particle beam out of the charged-particle source, and is connected to a pump for evacuating the inside. The charged-particle gun is characterized in having an opening for passing the charged-particle beam through, and in providing a barrier in a region connecting the charged-particle source and the opening. Consequently, molecules present in a downstream-side vacuum chamber which is low in degree of vacuum are prevented from being attracted to the charged-particle source through the opening, and current noise is reducible. The charged-particle beam device thereby stably operates.