A binder cartridge (51) that can accommodate a large number of binders (61) , which are connected in parallel to each other by an engaging mechanism. A right angle crank-shaped guide groove (55) is formed in a gate portion (54) at the front end of the binder cartridge. A binder in the front row of the binder cartridge is moved by a binder lateral movement mechanism (7) along the crank-shaped guide groove in the lateral direction and is separated from the other binders. A pair of upper and lower pushers (12, 13) of a bind mechanism portion (5) pinch division ring portions of the binder in the vertical direction and insert the division ring portions into a punch hole formed on the sheets of paper.