The objective of the present invention is to propose a charged particle beam device with which an imaging optical system and an irradiation optical system can be adjusted with high precision. In order to achieve this objective, provided is a charged particle beam device comprising: a first charged particle column which serves as an irradiation optical signal; a deflector that deflects charged particles which have passed through the inside of the first charged particle column toward an object; and a second charged particle column which serves as an imaging optical system. The charged particle beam device is provided with: a light source that emits light toward the object; and a control device that obtains, on the basis of detection charged particles generated according to irradiation of light emitted from the light source, a plurality of deflection signals which maintain a certain deflection state, and that selects or calculates, from the plurality of deflection signals or from relationship information produced from the plurality of deflection signals, a deflection signal that satisfies a predetermined condition.