The present invention provides a sheet processing apparatus comprising a sheet holding device capable of storing supplied sheets, a first sheet stacking tray on which sheets are stacked at a downstream side of the sheet holding device in a sheet conveying direction and on which the sheets are subjected to processing, a sheet discharging device for discharging the sheets stacked on the first sheet stacking tray, a second sheet stacking tray on which the sheets discharged by the sheet discharging device are stacked, and a controller for controlling the sheet discharging device and the sheet holding device if sheet jam occurs at an upstream side of the sheet holding device, in such a manner that, after the sheets on the first sheet stacking tray are discharged onto the second sheet stacking tray, the sheets stored in the sheet holding device are discharged onto the first sheet stacking tray.