Disclosed is a pattern inspection apparatus which easily and highly accurately detects a profile error (deviation) of at least one pattern having a cross section with projections and recesses. The inspection apparatus for the pattern 32 is for detecting the profile error of the pattern having a cross section with a projection and a recess. This inspection apparatus includes a plate 30 on which a pattern is mounted, light sources 40, 42 and 44 which can change angles of illuminating light emitted onto the pattern, within a range of 15 to 75 degrees with reference to the top surface of the pattern, and photodetectors 52 and 54 which can receive reflected light from the pattern at an angle within a range of 15 to 75 degrees with reference to the top surface of the pattern. The inspection apparatus is characterized by that the profile error of the pattern is detected based on an amount of the reflected light from an edge between the top surface and the side surface of each of the patterns.