The present invention provides an image processing device that avoids occurrence of unintended color conversion during the logical operation processing, and produces high-resolution images. In the image processing device of the present invention, after an input color conversion unit converts the RGB color space into the CMYK color space, a first color conversion unit executes color conversion of an area subjected to the logical operation processing into the CMY color space, and a logical operation unit executes the logical operation processing. Thereafter, a second color conversion unit executes color conversion of a logical operation result into the CMYK color space. On the other hand, a pixel value comparison unit compares the color values of the CMY color space before and after the logical operation by the logical operation unit; and if coincident, an output image selection unit selects the color values converted by the input color conversion unit as they are. Thereby, as a result of the logical operation, if the color values of the images are not varied, the original color values in the CMYK color space are adopted as the output result; and therefore, there will not be unintended color conversion executed by the first and second color conversion units.