In order to provide an edge emphasis technique that can eliminate image deterioration of a digital image, an image processing apparatus includes a region setting unit which sets a region including a pixel of interest, a brightness value derivation unit which derives brightness values of the pixels, a first derivative derivation unit which derives first derivatives of the brightness values derived by the brightness value derivation unit, an edge direction determination unit which determines an edge direction of brightness at a position of the pixel of interest based on the results of the first derivatives, a range determination unit which determines a range, and a replacement unit which replaces the pixel value of the pixel of interest.