To detect a bridge defect between lines of a line pattern formed on a sample at pitches narrower than the wavelength of inspection light, a defect inspection device is configured to comprise: a light source which emits laser; a vertical illumination unit which applies the laser to the sample from a vertical direction via an objective lens by converting the laser into linearly polarized light by using a polarization conversion unit in a state polarized in a direction orthogonal to the longitudinal direction of the line pattern; an oblique illumination unit which applies the laser to the sample from an oblique direction; a detection optical unit including an optical filter which selectively transmits a scattered light component from the defect by converting the polarization state of the reflected/scattered light; and a signal processing unit which detects the defect on the sample by processing a detection signal.