A charged particle beam device that can improve machining position precision in section processing using a shielding plate is provided. The invention is directed to a charged particle beam device including: an ion source (101); a sample stand (106) on which a sample (107) is mounted; a shielding plate (108) placed so that a portion of the sample (107) is exposed when seen from the ion source (101); and tilt units (123, 124) that tilt the sample (107) and the shielding plate (108) relative to the irradiation direction of an ion beam (102) from the ion source (101) to the sample (107).