In order to eliminate image deterioration based on the characteristics of an output device upon execution of edge emphasis processing, an image processing apparatus includes a setting unit which sets a print characteristic on the print medium, a region setting unit which sets a region, a brightness value derivation unit which derives brightness values, a first derivative derivation which derives first derivatives of the brightness values, an edge direction determination unit which determines an edge direction of brightness, an emphasis level determination unit which determines an emphasis level of a pixel value based on the first derivatives, and a replacement unit which calculates second derivatives of brightness values and replaces a pixel value of a pixel of interest based on the sign of the second derivative.