A sheet processing apparatus includes a processing tray to place the sheet, a load tray provided on a downstream side of the processing tray in a transport direction, neat alignment plates provided outside a main body housing to shift in a width direction orthogonal to the transport direction and to align opposite sides of the sheet, a sheet support surface provided in a different position adjacent to the processing tray to support a sheet inserted from a manual feed opening, a binding processing apparatus to perform binding processing on sheets placed on the sheet support surface, a regulation surface to regulate a side edge of the sheet located at a side of the load tray, and a width-direction drive mechanism to shift the neat alignment plates between an alignment position aligning a sheet on the load tray in the width direction and a retract position different from the alignment position.