Abstract: The present apparatus includes: a light emitting portion for emitting a detection-receiving light; a light emitting portion arranged parallel to the light emitting portion for emitting a detection-receiving light; a reflecting plate which is moved relative to the light emitting portions along their parallel arranged direction and also includes an optical pattern where a white area and a black area having a reflectance different from the white area with respect to the detection-receiving lights and are arranged alternately; and a light receiving portion which, according to the light intensities of the detection-receiving lights to be reflected by the reflecting plate, outputs output voltage signals. A controller selects one of the output voltage signals as a position detecting signal and obtains information about the position of a moving lens movable in linking with the reflecting plate.