PURPOSE: To minimize distance measurement parallax with simple constitution by projecting a light beam on a subject and moving an element which receives its reflected light and a lens toward a photographic lens in one body.

CONSTITUTION: The reflected light of the light beam projected on the subject S from a projecting element 1 through a projection lens 2 is photodetected by a photodetecting element 4 through a photodetection lens 3. When the subject S comes closer from infinite distance RO to distance R1, distance measurement parallax A is generated, so the lenses 2 and 3 are put close to the photographic lens 8 by distance (d) in one body, so that the distance measurement parallax becomes extremely small. A holders 19 which supports the lenses 2 and 3 integrally is energized by a spring 23 and abuts on the cam surface 24 of the distance ring of a lens 8 through a cam follower part 20. The lenses 2 and 3, therefore, move to the lens 8 according to the focusing operation of the lens 8, so the parallax of the distance measurement visual field is eliminated by the simple constitution.