A defect inspection system is provided which comprises an image acquiring section for acquiring a two-dimensional image of a subject which is a processing target in a manufacturing process, a defect extracting section for extracting a defect by a defect extraction algorithm using a predetermined parameter for an image acquired by the image acquiring section, a displaying section for displaying an image of a defect of the subject extracted by the defect extracting section, a parameter adjusting section for adjusting the parameter in accordance with a defect extraction degree for the subject, and a quality judging section for judging the quality of the subject based on a defect information extracted by the defect extracting section.