A post-processing apparatus includes a post-processing section configured to execute post-processing on a sheet conveyed from an image forming section, and a controller configured to set a first post-processing speed or a first number of sheets to be post-processed if the post-processing section is performing the post-processing on first sheets, and a second post-processing speed or a second number of sheets to be post-processed if the post-processing section is performing the post-processing on second sheets. The second sheets are sheets that have been decolored at least a predetermined number of times, and the first sheets are sheets that have been decolored less than the predetermined number of times.