Charged particle beam device

A charged particle beam device, comprising:

• a lens barrel that irradiates a sample with a charged particle beam;
• an imaging unit that images an optical image of the sample;
• a sample table on which the sample is placed;
• a stage that is movable and on which the sample table is placed, wherein
• the sample table includes a sample base portion that is arranged below a lower end of the sample table and placed on the stage, and a disposition table arranged above an upper end of the sample table, an observation portion of the sample being located at a center of the disposition table, and
• a distance q between a central axis of the sample base portion and a central axis of the disposition table satisfies q≥L−a, L being a distance between an optical axis of the lens barrel and an optical axis of the imaging unit and a being a distance that the stage is moved;
• a housing that supports the lens barrel;
• and
• a mirror that is disposed between the lens barrel and the imaging unit, wherein
• the imaging unit is disposed on a side surface of the housing and includes an imaging lens with respect to the mirror, and the optical axis of the imaging unit is an optical axis reflected by the mirror.