A sheet discharging apparatus includes an apparatus body, a discharge unit discharging a sheet out of the apparatus body, and a sheet stacking portion including a stacking surface on which the sheet discharged by the discharge unit is stacked. A sheet processing device processing the sheet discharged by the discharge unit can be mounted on the sheet stacking portion. The sheet discharging apparatus further includes a stiffness imparting unit removably attached to the apparatus body and imparting stiffness to the sheet discharged by the discharge unit. The stiffness imparting unit includes a pressing portion pressing and deflecting the sheet in a width direction intersecting with a sheet discharging direction and a projecting portion projecting from the apparatus body above the stacking surface such that at least a part of the projecting portion overlaps with the stacking surface in a plan view.