In case of forming images of a job, which includes color pages and black/white pages, in order to constitute a system which can obtain pages of individually formed images with a state in original page order by selectively using both a color image formation apparatus and a monochrome image formation apparatus with a simple operation, job contents are transferred to each of the color image formation apparatus and the monochrome image formation apparatus when the job, which includes the color pages and the black/white pages, is outputted from a computer. The color image formation apparatus forms only images of color pages, and then an user sets the color pages in an inserter. The monochrome image formation apparatus forms monochrome images when pages are black/white and feeds sheets from the inserter when pages are color.