A defect inspection device, which inspects defects such as foreign materials existing on a specimen on which a circuit pattern of wiring or the like is formed, is provided with an illumination optical system which illuminates a plurality of different areas the specimen with a plurality of linear shaped beams and an image forming optical system that forms images of the plurality of the illuminated areas on a plurality of detectors, and the detectors are configured to receive a plurality of polarization components substantially at the same time and individually, wherein the polarization components are different from each other and are contained in each of the plurality of the optical images formed by the image forming optical system, thereby detecting a plurality of signals corresponding to the polarization components and carrying out the inspection at high speed under a plurality of optical conditions.