Foreign matter inspection device and foreign matter inspection method

The present invention provides a foreign matter inspection device and method for reducing erroneous detection caused by diffracted light of a pattern and inspecting foreign matter adhering to a substrate (W) on which the pattern is formed, the foreign matter inspection device comprising: a light irradiation unit (2) for linearly scanning the substrate (W) and irradiating laser light (LB); a first light detection unit (3A) and a second light detection unit (3B) that detect light reflected by the substrate (W); and a foreign matter detection unit (4) that detects a foreign matter on the basis of output signals from the first light detection unit (3A) and the second light detection unit (3B), the first light detection unit (3A) and the second light detection unit (3B) being disposed such that a light receiving elevation angle (alpha) with respect to the surface of the substrate (W) and a light receiving horizontal angle (beta) with respect to the scanning direction of the laser light (LB) are different from each