In a defect inspection device (100), a processed image generation unit (61) of an image generation device (1) generates processed image data constituted by gradation information-storing bit strings, wherein gradation information representing gradation values corresponding to feature values for defective pixels is stored, and gradation information representing gradation values of zero for the remaining pixels is stored. An analysis image generation unit (62) generates analysis image data constituted by analysis bit strings obtained by adding defect information-storing bit strings, wherein defect information is stored, to the gradation information-storing bit strings, for each pixel.