To reduce the number of parts and to simplify the assembling work by connecting one end of a conductive member constituting an armature sliding on the pattern part of a driven sprocket for detecting the feed of the film to a control substrate in constitution where the rotation of the sprocket is converted into an electrical signal by the armature.

A tooth provided on the outer periphery of the sprocket 33 projects from an aperture 35 formed just above the image frame 34 of a main body 3 to a film guide part 36 and is meshed with the perforation of the film. The pattern part 38 consisting of a conduction part and a non-conduction part is provided to be rotated integrally with the sprocket 33, and the armature 40 provided at one end of the conductive member 39 whose other end is connected to the control substrate slides on the pattern part 38. The sprocket 33 is rotated in accordance with the feed amount of the film 43. In such a case, the electrical signal in proportion to the rotational amount of the sprocket is fetched from the armature 40 of the member 39 sliding on the pattern part 38 consisting of the conduction part and the non-conduction part.