A cut chip of a staple leg cut by a cutter unit is discharged to a lower face side of the cutter unit by way of an opening formed at the cutter unit. The cut chip is guided in directions of both sides of the stapler by a pair of chutes arranged on a lower face side of the cutter unit to be continuous to the opening portion. The cut chip guided by the chutes is guided to a containing portion formed at a rear lower portion of the stapler by way of guide case portions formed at both side faces of the stapler.