A sheet processing device having punch processing device(s) for punch-processing on a conveyed sheet member and a punch-scrap storage box for storing punch scraps therein that are produced by the punch processing and dropped from the punch-processing device(s) having an increased storing capacity of punch scraps, including a punch-scrap storage box constituting an air distribution duct having a punch-scrap suction inlet and an air discharge outlet; and air-sucking device(s) (fan) arranged on the most downstream side in the air discharge outlet of the air flowing direction for conveying the punch scraps produced by the punch processing device(s). Air is sucked by the fan so as to catch the punch scraps with punch-scrap separating device(s) arranged on the upstream side of the air flowing direction of the fan so that the punch scraps are heaped within the punch scrap storage box.