An inspection system of an embodiment includes: a planar illumination unit that temporally varies an intensity of light in a periodic manner by spatially moving a stripe pattern of the intensity of light; a time-correlation image generator that generates a time-correlation image with a time-correlation camera or an image capturing system that performs an operation equivalent to that of the time-correlation camera; and a calculation processor that calculates a characteristic from the time-correlation image, the characteristic corresponding to a distribution of normal vectors to an inspection target surface and serving to detect an abnormality based on at least either a difference from a surrounding area or a difference from a reference surface.