A sheet processing apparatus includes a sheet stacking member for temporarily receiving a sheet conveyed thereto and stacking the sheet thereon and a conveyance unit for outputting the sheet stacked on the sheet stacking member therefrom, wherein the conveyance unit includes a sheet output face having a predetermined acute angle with respect to a sheet stacking face of the sheet stacking member and configured to output a stack of sheets by touching a back end of the stack of sheets and pushing the stack of sheets.