A film end detector for use in automatic film winding camera comprises a rotary disc having a light transmitting area and mounted on the drive shaft of a motor which is used to wind up a film automatically. The rotation of the disc is monitored by a combination of a light source and light receiving, photoelectric transducer element which are disposed to monitor the passage of light through the light transmitting area, thus detecting a film end. Logic circuits examine the output of the photoelectric transducer element at predetermined intervals to ascertain the completion or failure of completion of a normal film-winding operation.