A sheet processing apparatus having a laser processing unit, a collecting portion, and a detecting portion. The collecting portion is disposed below a laser processing position of the laser processing unit. The collecting portion collects a scrap of the sheet produced when the sheet is processed by the laser processing unit. The detecting portion is configured to detect the scrap collected into the collecting portion and reaching a predetermined height. A detection position of the detecting portion is lower than a processing range of the laser beam where processing by the laser beam is possible.