PURPOSE: To protect the leading end of a medium so as to prevent the leading end of the medium from being damaged, broken and so forth when it make contact with a gate roller after curling.

CONSTITUTION: In a medium separating mechanism, a plurality of mediums 1 fed by a pick-up roller 2, are separated from one another by a gate roller 5 so that the mediums 1 on the pick-up roller 2 side are successively drawn out one by one and fed. Further, a gate roller guide 7 is provided on the inlet side of a gate roller 5, and accordingly, in such a case that the leading end of a sheet curls toward the gate roller 5, the leading end of the medium 1 fed out by the pick-up roller 2 abuts against the gate roller 7, and accordingly, moves, sliding on the surface of the gate roller guide 7.