Foreign matter inspection apparatus and foreign matter inspection method

An invention is a foreign matter inspection apparatus, reducing false detection caused by diffracted light of a pattern, and inspecting foreign matter attached to a substrate on which the pattern is formed, and includes: a light irradiation part scanning the substrate in a line shape and irradiating the substrate with laser light; a first light detection part and a second light detection part detecting light reflected by the substrate; and a foreign matter detection part detecting foreign matter based on output signals of the first light detection part and the second light detection part, wherein the first light detection part and the second light detection part are arranged so that a light-receiving elevation angle with respect to a surface of the substrate and a light-receiving horizontal angle with respect to a scanning direction of the laser light are different from each other, wherein the first light detection part detects diffracted light from the pattern whose angle with the scanning direction is a pre