Provided is a charged particle beam apparatus capable of realizing a highly reliable insulating structure. This charged particle beam apparatus emits a charged particle beam from a charged particle beam emission device onto a sample, detects charged particles generated from the sample, and creates a sample image or processes the sample. The charged particle beam emission device is provided with a charged particle source and a shield arranged in an interior of a metal housing that is filled with an insulating gas, and an acceleration electrode arranged below the charged particle source, power being supplied to the acceleration electrode via the shield.