To efficiently operate an image forming system while output of sheets of waste paper is minimized when a job is specified for sheets of paper exceeding a possible number in a paper process.

In an image forming system, an N number of sets, each of which consist of a paper bundle of an M number of sheets of paper, are used based on input job data, and image formation by an image forming apparatus 100 and a paper process by a paper processing device 300 are carried out to output sheets of paper. In this case, if N is equal to or smaller than a specified regulated number of sets when M exceeds a number of sheets of paper that a paper processing part can process, images are formed on sheets of the M number of sheets×N sets in an image forming part. Also, a paper process by the paper processing part is not carried out for sheets of paper with images formed thereon, and the sheets of paper are ejected to a sheet ejection part different from one used in normal time.