Signal electrons with high energy that pass near an optical axis, for example, backscattered electrons or secondary electrons in a booster optical system, can be detected. Therefore, there is provided a charged particle beam device including: a charged particle beam source configured to generate a charged particle beam; an objective lens configured to focus the charged particle beam to a sample; and a first charged particle detecting element disposed between the charged particle beam source and the objective lens and configured to detect charged particles generated by an interaction between the charged particle beam and the sample, in which a detection surface of the first charged particle detecting element is disposed on a center axis of the objective lens.