Abstract: Advancing system of film compartment for cameras includes a film compartment lever on compartment cover between film shaft and gear, then on one side of the gear is equipped with a transmission gear, and a friction spring is equipped below that gear to contain an engaging block. Thus, as the engaging block follows the gear and the transmission gear to rotate, the engaging block can stop at two corresponding stops and immobilize the lever despite whether the film is in a loaded photo-ready or retracted position, to ensure and avoid the film compartment cover from opening. Furthermore, a transmission cover plate is equipped atop the gear, while the top side of the cover plate is equipped with positioning brass piece that engage with the circuit control board located at the very top side to facilitate the contact of the positioning brass piece and the brass soldering on the circuit control board.