The present invention is to provide a staple cartridge that can offset any discrepancies when mounting a staple cartridge, even if staples are slightly offset to check the occurrence of stapling defects. The staple cartridge 100 of the holding means 200 which is equivalent to the cartridge holder disposed as either a body separate to the stapler unit 300 or unitized thereto, actuates the staple feeds means 202. Even if the position of the staple pulled out from the staple cartridge is offset, this action corrects the offset to correctly set the staple at the driving position thereby enabling it to check stapling defects that occur because of mis-positioning of the staple set position.