The invention provides a defect inspection method and a defect inspection device which enable a defect to be inspected regardless of optical conditions. The invention comprises the steps of setting a target local region and a plurality of corresponding local regions in the image signals, the target local region including a target pixel and an area surrounding the target pixel, the corresponding local regions including pixels corresponding to the target pixel and areas surrounding the corresponding pixels; searching similarities between the image signal of the target local region and the image signals of the plurality of corresponding local regions; determining a plurality of image signals that represent corresponding local regions and are similar to the image signal of the target local region; and comparing the image signal of the target local region with the image signals that represent the corresponding local regions.