PURPOSE: To increase the speed of a stapling process by starting the movement of a stapler based on the point of time when the distributing operation of a distribution means is completed and moving the stapler at high speed when there is no danger of the collision with the distribution means.

CONSTITUTION: The home position of a distribution means 13 is set to the opposed position of the distribution bin 2 positioned at one end of the arranging direction of distribution bins 2 and the home position of a stapler unit 30 is set in the vicinity of the distribution bin 2 positioned at the other end of the arranging direction of the distribution bins 2. The first control means of the distribution means 13 intermittently moves the distribution means 13 in the first direction separated from the opposed position of the distribution bin 2 positioned at one end of the arranging direction of the distribution bins 2 and the second direction approaching the opposed position. The second control means thereof starts the movement of the stapler unit 30 at the first speed when the distribution means 13 completes distributing operation by the movement in the first direction and starts the movement of the stapler unit 30 at speed higher than the first speed when the distribution means 13 completes distributing operation by the movement in the second direction.