The purpose of the present invention is to provide a sheet bundle binding processing apparatus capable of providing relatively strong bonding when a plurality of sheets are bound by corrugation-shaped pressurizing faces with nip-pressure deformation and causing less frictional damage on a sheet face when a sheet bundle is introduced to and discharged from the binding unit. The present invention comprises a sheet bundle binding processing apparatus including a processing tray which includes a sheet placement face on which sheets are stacked, a press binding device which bonds mutually overlapped sheets stacked on the processing tray with pressure-bonding deformation, a taking-off device which applies a taking-off force to sheets bound by the press binding device along the sheet placement face for taking off the sheets from the press binding device, and a sheet bundle discharging device by which the sheets taken off from the press binding device by the taking-off device is discharged from the processing tray.