The color determination circuit 308 detects hue of the color image information, and the controller 205 decides a color component to be separated (separation color) in accordance with the detected hue. Output color by the printer 204 is set in correspondence with the separation color. The two-color-separating circuit 303 separates the color image information into image information on at least two color components in accordance with the decided separation colors. The separated image information on the each color is transmitted to the printer 204 via printer density correction circuits 304 and 305, and a buffer 306. Thereby it is possible to provide an image processing apparatus capable of setting and changing the separation color and the output color by automatic operation or by simple manual operation, thus the expression of the image forming can be improved.