PURPOSE: To remarkably easily sort and file after the binding in the case when a large amount of output recording paper is stacked and accumulated at night, on a holiday or the like by processing a specific number of sheets of sheet materials successively output and grouped with each other in a condition that they are bound every group as a booklet.

CONSTITUTION: A point side 8b of the recorded paper entered into a pocket space 26 is collided with a bottom face 22B to be received, moved outside of a device in the looped state, cut by the cutter blades 13, 14, and suspended outside of a holder plate 22 by the self-weight. The received recording paper of second page, third page... are successively overlapped and suspended in the same way. An inner face of an anvil 44 of a stapler unit 30 is positioned outside corresponding to a point side right corner of the recording paper 81, 82, 83..., only one piece of the top staple 52A in a staple magazine is pushed out so that both legs thereof are penetrated through the paper, and bent inward to each other by the anvil 44 whereby the recording paper is bound as a booklet. Then a long moving plate 38 is projected outward from a cut window part 22C, and a point of the paper is released outward.