According to the present invention, a stacking face (84) is inclined such that a downstream side in a sheet discharging direction is lower, and is composed of a first supporting face (84a) supporting a sheet to be stacked at its front end part in a sheet discharging direction and a second supporting face (84b) supporting the sheet to be stacked at its rear end part in the sheet discharging direction. The first supporting face (84a) is structured to be shorter than ½ of a minimum size length of the sheet to be stacked, and this is provided rotatably upward around a rotating shaft (85x) furnished to a registration part (85r) of regulating the front ends of the sheets. The first supporting face (84a) raises the front ends of the sheets to be discharged by rotation of the registration part (85r).