An image processing apparatus comprising: an illuminating section (105, 200) 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 at a right angle with the first direction in a polarization image capturing mode and which irradiates the object with a non-polarized illuminating light beam in a non-polarization image capturing mode, the illuminating section emitting the first and second illuminating light beams sequentially so that the wavelength range of the first illuminating light beam does not overlap with the wavelength range of the second illuminating light beam somewhere; an image sensor including a polarization mosaic array in which a plurality of polarizers with mutually different polarization transmission axis directions are arranged and a photosensing element array which receives light that has been transmitted through each said polarizer and which outputs a signal; a polarization mosaic processing section which obtains, in the polarization image capturing mode, a first polarization image to be generated based on a signal representing light that has been transmitted through a polarizer that has the polarization transmission axis in a direction intersecting with the first direction at a right angle while the object is being irradiated with the first illuminating light beam and a second polarization image to be generated based on a signal representing light that has been transmitted through a polarizer that has the polarization transmission axis in a direction intersecting with the second direction at a right angle while the object is being irradiated with the second illuminating light beam, and which obtains, in the non-polarization image capturing mode, a non-polarization image to be generated based on a signal representing light that has been transmitted through each said polarizer while the object is being irradiated with the non-polarized illuminating light beam; a depressed area detecting section which detects a depressed area on the surface of the object based on at least one of the first and second polarization images by detecting through a differentiation processing a pixel region that is brighter than a surrounding area; and an image forming section which forms an image that represents the depressed area on the object's surface in an enhanced form. an illuminating section (105, 200) 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 at a right angle with the first direction in a polarization image capturing mode and which irradiates the object with a non-polarized illuminating light beam in a non-polarization image capturing mode, the illuminating section emitting the first and second illuminating light beams sequentially so that the wavelength range of the first illuminating light beam does not overlap with the wavelength range of the second illuminating light beam somewhere; an image sensor including a polarization mosaic array in which a plurality of polarizers with mutually different polarization transmission axis directions are arranged and a photosensing element array which receives light that has been transmitted through each said polarizer and which outputs a signal; a polarization mosaic processing section which obtains, in the polarization image capturing mode, a first polarization image to be generated based on a signal representing light that has been transmitted through a polarizer that has the polarization transmission axis in a direction intersecting with the first direction at a right angle while the object is being irradiated with the first illuminating light beam and a second polarization image to be generated based on a signal representing light that has been transmitted through a polarizer that has the polarization transmission axis in a direction intersecting with the second direction at a right angle while the object is being irradiated with the second illuminating light beam, and which obtains, in the non-polarization image capturing mode, a non-polarization image to be generated based on a signal representing light that has been transmitted through each said polarizer while the object is being irradiated with the non-polarized illuminating light beam; a depressed area detecting section which detects a depressed area on the surface of the object based on at least one of the first and second polarization images by detecting through a differentiation processing a pixel region that is brighter than a surrounding area; and an image forming section which forms an image that represents the depressed area on the object's surface in an enhanced form.