An image processing apparatus according to the present disclosure includes an illuminating section which sequentially irradiates an object with a first illuminating light beam that is polarized in a first direction and with a second illuminating light beam that is polarized in a second direction that intersects with the first direction in a polarization image capturing mode. In the polarization image capturing mode, obtained are first and second polarization images to be generated based on signals representing light that has been transmitted through polarizers that have the polarization transmission axis in respective directions that are parallel to, and intersect with, the first direction while the object is being irradiated with the first illuminating light beam, and third and fourth polarization images to be generated based on signals representing light that has been transmitted through polarizers that have the polarization transmission axis in respective directions that are parallel to, and intersect with, the second direction while the object is being irradiated with the second illuminating light beam. And a depressed region on the surface of the object is detected based on the first and second polarization images that form one pair and/or the third and fourth polarization images that form another pair.
