Input print data can assume one of a RGB color space, CMYK color space, and Gray color space. When graphic arts are principally to be printed, data of these color spaces is converted into CIE Color Space XYZ as a standard color space, and data of the standard color space is converted into a CMYK color space according to the Output Profile of a printer, which then prints the converted data. On the other hand, when office documents are principally to be printed, conversion into the standard color space is skipped, and input color space data is directly converted into a print color space CMYK, and the converted data is then printed.