To discharge a sheet determined to be defective in inspection processing, without binding it, and to replace the defective sheet by a sheet to be additionally output, even when binding processing is specified as job processing.

An inspection system including an inspection means that reads an image on a conveyed sheet and inspects whether an image output onto the sheet is normal or not includes: a post-processing means for binding a plurality of stacked sheets with images printed thereon, according to the specification of a job; a detection means for detecting the conveyance position of the sheet determined by the inspection means that the image on the sheet is defective; and a control means for discharging the sheet to a first discharge destination, without binding it by the post processing means specified to the sheet determined to be defective and to the sheet bundle stacked before the sheet, according to the conveyance position of the sheet detected by the detection means, and discharging the sheet to be fed after the sheet with the defective image to a second discharge destination.