PURPOSE: To correct a sheet of copying paper being skewingly fed into a folder to be a normal arrangement by using rolls having a mutually different coefficient of friction to said sheet of paper.

CONSTITUTION: A first folder roll 1 is provided so that its rotary shaft intersects obliquely with the rotary shaft of a second folder roll 2 at an angle α. An edge of a sheet of paper being skewingly fed is brought in contact with a feeding direction correcting wall 7. In this case, the sheet of paper P is further kept feeding from the upper part to the lower part by means of the rolls 1 and 2 but, since the friction coefficient to the sheet of paper is mutually different between the folder roll 1 and the folder roll 2, a slippage takes place between the paper surface, which is in contact with the roll having a smaller friction coefficient, and the roll when the sheet of paper is fed downward with its bottom end being kept in contact with a lower stopper 5. Thereby the paper is moved in the direction of arrow A and its advancing direction is corrected to be a normal condition, moving along the feeding direction correcting wall 7.