PURPOSE: To renew the friction application surface of a retard roller every time and prevent double feeding for a long time by rotating the retard roller facing a feed roller by a fixed angle in interlock with the insertion work of the paper.

CONSTITUTION: A feed roller 12 and a retard roller 13 are provided at the tip of the bottom plate 11a of a paper stacker 11, and a trigger roller 14 is provided inside the bottom plate 1a. In this case, a claw wheel 18 is provided at the end of the shaft 13a of the retard roller 13, and the other end of an arm 19 having a claw 19a coupled with the claw wheel 18 at one end is connected to a cover 15 with a pin 20. When the cover 15 is opened to load the new paper 17 in the paper stacker 11, the arm 19 is moved to the right to rotate the claw wheel 18, and the retard roller 13 is rotated by a fixed angle. Thereby, the surface of the retard roller 13 facing the feed roller 12 is made a new surface, thus giving sufficient friction resistance to the paper 17.