Provided is an apparatus for inspecting the back surface of an epitaxial wafer, capable of detecting defects in the back surface of an epitaxial wafer. An epitaxial wafer back surface inspection apparatus has an optical system including an annular fiber optic illuminator and an imaging unit which are placed perpendicular to the back surface of an epitaxial wafer; and a scanning unit operating the optical system in parallel with the back surface to scan the back surface. A light source of the annular fiber optic illuminator is composed of either blue LEDs or red LEDs.