The present invention enables automatic generation of an image in which only an impressive color is kept, without requiring a complicated operation. A digital camera 100 divides an image obtained by an imaging unit 20 into regions based on color information and luminance information, and determines a characteristic object in accordance with a characteristic degree of each region into which the image is divided. Further, a region for keeping a color is set in which the color of the characteristic object is to be kept. A color conversion process is then performed so as to keep the color of the characteristic object in the region for keeping a color, and to change colors of the other regions to an achromatic color.