A surface inspection device (100; 100A; 100B) for inspecting a sample surface, comprising: an opening defining an aperture plane for measurement; a plurality of measurement units (10, 20; 10, 20, 30; 10d, 20d, 30d) each including a light emitting section (11, 21; 11, 21, 31; 11d, 21d, 31d) and a light receiving section (12, 22; 12, 22, 32) and arranged in different directions with respect to the aperture plane when viewed from above a virtual normal line of the aperture plane; an acquiring section (72; 72A) configured to acquire, for each measurement unit (10, 20; 10, 20, 30; 10d, 20d, 30d), a detection value of brightness of light emitted from the sample surface (Ssl) in response to light irradiation from the light emitting section (11, 21; 11, 21, 31; 11d, 21d, 31d) via the aperture plane and received by the light receiving section (12, 22; 12, 22, 32) via the aperture plane; and a calculation section (73; 73A) configured to calculate an evaluation value of a degree of variation in the multiple detection values acquired for the plurality of measurement units (10, 20; 10, 20, 30; 10d, 20d, 30d) by the acquiring section (72; 72A), wherein a first angle between a first optical path of light from the light emitting section (11, 21; 11, 21, 31; 11d, 21d, 31d) toward the aperture plane and the normal line of the aperture plane, a second angle between a second optical path of light from the aperture plane toward the light receiving section (12, 22; 12, 22, 32) and the normal line, and a third angle between the first and second optical paths (Pr1, Pr2) are equal among the plurality of measurement units (10, 20; 10, 20, 30; 10d, 20d, 30d). an opening defining an aperture plane for measurement; a plurality of measurement units (10, 20; 10, 20, 30; 10d, 20d, 30d) each including a light emitting section (11, 21; 11, 21, 31; 11d, 21d, 31d) and a light receiving section (12, 22; 12, 22, 32) and arranged in different directions with respect to the aperture plane when viewed from above a virtual normal line of the aperture plane; an acquiring section (72; 72A) configured to acquire, for each measurement unit (10, 20; 10, 20, 30; 10d, 20d, 30d), a detection value of brightness of light emitted from the sample surface (Ssl) in response to light irradiation from the light emitting section (11, 21; 11, 21, 31; 11d, 21d, 31d) via the aperture plane and received by the light receiving section (12, 22; 12, 22, 32) via the aperture plane; and a calculation section (73; 73A) configured to calculate an evaluation value of a degree of variation in the multiple detection values acquired for the plurality of measurement units (10, 20; 10, 20, 30; 10d, 20d, 30d) by the acquiring section (72; 72A), wherein a first angle between a first optical path of light from the light emitting section (11, 21; 11, 21, 31; 11d, 21d, 31d) toward the aperture plane and the normal line of the aperture plane, a second angle between a second optical path of light from the aperture plane toward the light receiving section (12, 22; 12, 22, 32) and the normal line, and a third angle between the first and second optical paths (Pr1, Pr2) are equal among the plurality of measurement units (10, 20; 10, 20, 30; 10d, 20d, 30d).