The objective of the present invention is to provide an illuminating device for inspection, capable of carrying out detection even of feature points in which the change in reflection, transmission or scattering is very small, and which is capable of determining an amount of change in light in an observation solid angle of an image capturing device under constant conditions, even if only a slight change in reflection, transmission or scattering is caused at a feature point of an object being inspected. In the illuminating device for inspection there are disposed a surface light source 1 which emits inspecting light, at least one light-shielding mask M1 between the surface light source 1 and the inspection target W, and a lens 2 that is on the side of the light-shielding mask M1 that is closer to the inspection target W and is disposed in such a way that the light-shielding mask is located with the focal point position of the lens at the center of the light-shielding mask. By arranging that a dark region is formed by the light-shielding mask M1 in an illumination solid angle of the inspecting light relative to the inspection target W, formed when light emitted from the surface light source 1 is radiated onto the inspection target W by means of the lens 2, it is possible to modify the shape, size and angle of inclination of the inspecting light illumination solid angle in accordance with a change in reflection, transmission or scattering caused at a feature point of the object being inspected.