PURPOSE: To prevent double feed and to return an erroneously fed paper into a tray by making a separation roller spported at the tip of a supporting lever mountable/dismountable on/from a, paper feed roller from underside.

CONSTITUTION: When uppermost paper 1b is fed while being overlapped, an upper paper 1a is fed through rotation of a paper feed roller 17 in the direction B when it arrives to a gap between the paper feed roller 17 and a separation roller 19, and since the paper 1b is placed under the paper 1a, the separation roller 19 resumes rotation in the direction D so as to prevent feeding of the lower paper 1b. If a paper 1 is fed erroneously through rotation of a feed-out roller 12, it is detected through a detecting means at carrying side and a supporting lever 21 is rotated reversely from direction C based on a detection signal and the separation roller lg is isolated from a feed roller 18 and rotated in the direction D so as to return the erroneously fed paper 1 into a tray 2.