To improve operationality in color adjustment of an image quality, colored characters, or the like of a document including one of a character image, a photographic image, and a screened halftone image of chromatic or achromatic color, the invention comprises image processing means (36) for identifying a character area, a photographic area, and a screened halftone area of a document on the basis of a first parameter and determining whether one or more of the character area, the photographic area, and the screened halftone area of the document are chromatic or achromatic on the basis of a second parameter to perform image processing according to them; operation setting means (14) for setting the first and second parameters; and control means (15) for displaying a first parameter adjustment content for use in identifying one or more of the character area, the photographic area, and the screened halftone area of the document and a second parameter adjustment content for use in determining whether one or more of the character area, the photographic area, and the screened halftone area of the document are chromatic or achromatic on the same screen.