A bookbinding system that pastes a cover sheet on a sheet bundle, the bookbinding system includes: an image forming section which forms a toner image based on image data; a sheet storing section which stacks recording sheets on which toner images have been recorded by the image forming section, aligns the recording sheets thereby forming a sheet bundle; a heating member which applies heat to an adhesive to melt; a cover sheet pasting section which pastes a spine of the sheet bundle and a cover sheet with the adhesive melted by the heating member; and a controller which controls the image forming section. The controller controls the image forming section not to record the toner image based on the image data in the vicinity of an edge portion on a side of the spine of each of the recording sheets that constitute the sheet bundle.