Pattern inspection apparatus and pattern inspection method

A pattern inspection apparatus comprising:

• an optical image acquisition mechanism configured to acquire an optical image of an inspection target object on which a pattern is formed;
• a parameter range setting circuit configured to set a range of a reference image generation parameter according to a coincidence degree with a past inspection condition parameter;
• a filter function generation circuit configured to generate a plurality of filter function candidates, using values in a set range of the reference image generation parameter;
• a determination circuit configured to determine a filter function for generating a reference image in the plurality of filter function candidates generated;
• a reference image generation circuit configured to generate a reference image by using the filter function determined;
• and
• a comparison circuit configured to compare the optical image with the reference image, wherein
• the reference image generation parameter is at least one of a resize amount and a corner rounding amount.