A charged particle beam apparatus acquires a scanned image by scanning a specimen with a charged particle beam, and detecting charged particles emitted from the specimen. The apparatus includes a charged particle beam source that emits the charged particle beam; an irradiation optical system that scans the specimen with the charged particle beam; a plurality of detection units that detects the charged particles emitted from the specimen; and an image processing unit that reconstructs a profile of a specimen surface of the specimen, based on a plurality of detection signals outputted from the plurality of detection units. The image processing unit: determines an inclination angle of the specimen surface, based on the plurality of detection signals; processing to determine a height of the specimen surface, based on the scanned image; and reconstructs the profile of the specimen surface, based on the inclination angle and the height.