A defect image including a defect and a defect-free image not including a defect for an article different from an inspection article are acquired to teach an identifier when inspecting for a defect in the inspection article. The identifier that has learned the images is made to identify whether an extracted inspection image obtained by segmenting the inspection image of the inspection article includes the defect and the identification results of the identifier are used to determine whether a defect is present in the inspection article. When teaching the identifier the defect, the identifier is provided with, as learning images, a plurality of extracted defect images generated from the defect image by changing an extracting region for extraction from the defect image such that the defect in the defect image is at a different position in each of the plurality of extracted defect images.