A defect inspection method includes irradiating a sample with laser, condensing and detecting scattered light beams, processing signals that detectors have detected and extracting a defect on a sample surface, and outputting information on the extracted defect. Detection of the scattered light beams is performed by condensing the scattered light beams, adjusting polarization directions of the condensed scattered light beams, mutually separating the light beams depending on the polarization direction, and detecting the light beams by a plurality of detectors. Extraction of the defect is performed by processing output signals from the detectors by multiplying each detection signal by a gain, discriminating between a noise and the defect, and detecting the defect.