A sheet postprocessing device includes a saddle binding device configured to stack a plurality of recording sheets on a table, abut leading edges of the respective recording sheets against a leading edge cursor, thus to align the leading edges with each other, and bind the center of the recording sheets and fold the recording sheets, and a first pressing member supported so as to pivot in a direction toward and away from the table. The first pressing member is made to pivot toward the table by self-weight thereof, allows the leading edge of the recording sheet delivered to the table to pass toward the leading edge cursor, and presses a portion of the recording sheet in a proximity of the leading edge, at a position upstream of the leading edge cursor, in a delivery direction of the recording sheet.