According to the present invention, in a charged particle beam device having a charged particle source, an objective lens for focusing a primary-charged particle beam emitted from the charged particle source, a scan deflector for scanning the primary-charged particle beam on a sample, and a detector for detecting signal particles generated from the sample under scanning of the primary-charged particle beam, whereby a sample image is obtained by using the signal particles of the detector, the charged particle beam device comprises a deflector for deflecting an angle of irradiation of the primary-charged particle beam onto the sample, first and second independent power supplies for passing currents to the deflector, and a switch for switching over voltages applied from the two power supplies in unit of one line or one frame of scanning of the primary-charged particle beam.