There is provided a scanning transmission charged particle beam device by which charged particles of a bright-field image and charged particles of a dark-field image may be clearly separated, and bright-field images and dark-field images with high accuracy may be obtained even in a state in which the scanning range of a charged particle beams on a sample is changed.A deflecting coil is provided below a sample, and a charged particle detector for a dark-field image with an opening is provided below the deflecting coil. A charged particle detector for a bright-field image is provided below the above opening. By the deflecting coil below the sample, a charged particle beam for a bright-field image is configured to be synchronized with the scanning of a particle beam, and to be deflected in an opposite direction to the deflected direction of the particle beam. Thereby, a charged particles beam of a bright-field image passes through the opening of the charged particle detector for a dark-field image, and is detected by the charged particle detector for a bright-field image.