An apparatus removably mountable on an X-ray image photographing apparatus for supplying sheet films to the photographing apparatus is provided with an outlet, a chamber for holding a number of sheet films, a slit having a gap of such dimension into which a sheet film may enter, a transport member for transporting the outermost sheet to the outlet and prior to said transport, transporting that sheet film toward the slit, and a pressing member for downwardly curving the end of the remaining sheet films which is adjacent to the outlet.