Abstract: A sheet processing apparatus includes a plurality of sheet discharging means for discharging sheets; a plurality of intermediate trays for temporarily stacking the sheets discharged by the discharging means; processing means for processing the sheets; a tray for receiving and accommodating the sheet from the intermediate trays; control means for facing one of the intermediate trays to one of the discharging means to stack the sheets on the intermediate tray and moving the intermediate tray to permit the sheets to be processed by the processing means; then facing, during processing for the sheets on the one of the intermediate trays, another one of the intermediate trays to another one of the discharging means to stack the sheets on the another intermediate tray: then returning, after discharging the sheets from the one of the intermediate trays after processing the sheets thereon, the one of the intermediate trays to the one of the discharging means; then moving the intermediate try to permit the sheets to be