To reduce consumption of consumables by printing again to a failure portion of failed printed matter without intervention of a user's hand and while keeping a page order when the failed printed matter is generated.

The image forming apparatus 101 prints on a sheet conveyed on a paper transfer conveyance path 108 on the basis of printing image data 401, generates printed matter imaging data 402 by reading the printing surface of the printed sheet, determines whether or not printing to the sheet fails from the printing image data and printed matter imaging data, specifies the failure print portion of the sheet by comparing the printing image data and printed matter imaging data with each other when printing on the sheet is determined as a failure, generates overlay data 404 to be printed while being overlaid on the failure print portion, conveys again the sheet determined to fail in printing to the paper transfer conveyance path 108, and executes reprinting processing of printing the overlay data to the failure print portion of the re-conveyed sheet.