A pattern verification apparatus includes a correction section creating a plurality of first data pieces; a determination section performing light intensity simulation to create a plurality of plots, determine whether or not each of the plurality of simulation result plots falls within an allowable range, and recognize two or more simulation result plots which do not fall within the allowable range as a plurality of second data pieces; an extraction section extracting a reference pattern of the plurality of original design patterns corresponding to the plurality of second data pieces; and a classifying section classifying the plurality of second data pieces into categories of the reference pattern.