According to one embodiment, a defect inspection device includes a first beam splitter configured to branch light into a first optical path and a second optical path, a first optical system on the first optical path, a second optical system on the second optical path, a first aperture configured to form an illumination field of an inspection sample by light from the first optical system, a second aperture configured to form an illumination field of the inspection sample by light from the second optical system, and a third optical system configured to illuminate, with a first illumination, an image of the first aperture on a first area of the inspection sample, and to illuminate, with a second illumination, an image of the second aperture on a second area of the inspection sample.