A defect inspection device includes an irradiation unit for simultaneously irradiating different regions on a sample with illumination light under different optical conditions, the sample being predesigned to include patterns repeatedly formed thereupon, wherein the patterns are to be formed in the same shape; a detection unit for detecting, for each of the different regions, a beam of light reflected from each region irradiated with the illumination light; a defect candidate extraction unit for extracting defect candidates under the different optical conditions for each of the different regions, by processing detection signals corresponding to the reflected light which is detected; a defect extraction unit for extracting defects by integrating the defect candidates extracted under the different optical conditions; and a defect classifying unit for calculating feature quantities of the extracted defects and classifies the defects according to the calculated feature quantities.