Provided is a charged particle beam device to improve energy solution of its energy filter. In one embodiment, a charged particle beam device includes a deflector to deflect charged particles emitted from a sample to an energy filter, and a change in brightness value with the change of voltage applied to the energy filter is found for each of a plurality of deflection conditions for the deflector, and a deflection condition such that a change in the brightness value satisfies a predetermined condition is set as the deflection condition for the deflector.