PURPOSE: To cheaply manufacture a sheet feed mechanism simplified in its structure by providing a detecting means which contains a contactor displaced being associated with a sucker means.

CONSTITUTION: When air in a pipe body 18 is sucked by adapting a sucker disk to a film F in the uppermost position while driving a vacuum generator, the film F in the uppermost position is sucked being attached to this sucker disk 12. A contactor 24 of a detecting means 14, displaced with the sucker disk 12, is adapted to the film F. As the result, the contactor 24 moves tilting with a shaft 32 serving as the center, and a base end part 34 of this contactor 24 is fitted between a light projecting part 26a of a photointerrupter 22 and its light receiving part 26b. Consequently, intercepting light, projected from a light emitting diode of the light projecting part 26a, by the base end part 34b not to reach a photodiode of the light receiving part 26b, an electric current is not allowed to flow in a detecting circuit connecting this photointerrupter 22.