234 to actuate the limit switch for reversing the driving motor 211 consequently the drill 22 is lifted up to the original position so that the limit switch is actuated to stop the driving motor 211 and the drill motor 221 during this process the starting rod 31 which moves downwardly along with the retaining rod 243 of the pressing member 24 is stopped when the downward movement of the pressing member 24 is stopped after sufficiently pressing the papers however the supporting plate 222 supporting the drill 22 is allowed to move further downward so that the actuating piece 224 of the supporting plate 222 comes to depress the pressing portion 317 of the starting rod 31 immediately before the arrival of the drill end at the surface of the papersa to be bound thereby to restart the downward movement of the starting rod 31 the downward movement of the starting rod 31 is continued from an instant immediately before the commencement of the boring through the papers a by the drill 22 until the boring is completed consequently the lower engaging piece 312 of the starting rod 31 is lowered from the engaging portion 313 of the retaining rod 243 by a length corresponding to the length of the stacked papers a so as to pull the tow rope 32 the rotation of the rope taking up roller 322 is caused as the rope 32 is pulled so that the feed roller 33 is also.