PATTERN INSPECTION APPARATUS AND PATTERN INSPECTION METHOD

A pattern inspection apparatus includes an illumination optical system to illuminate an inspection substrate on which a pattern is formed, an offset calculation circuit to calculate an offset amount which depends on an image accumulation time of each of a plurality of photo sensor elements arrayed two-dimensionally, a time delay integration (TDI) sensor to include the plurality of photo sensor elements, to acquire an image of the inspection substrate by receiving a transmitted light or a reflected light from the inspection substrate by the plurality of photo sensor elements, to correct, using the offset amount, a pixel value of optical image data of an acquired image, and to output the optical image data having been corrected, and a comparison circuit to compare an optical image formed by the optical image data output from the TDI sensor with a reference image.