A first movable barrel is rotated and moved along an optical path by driving force of a motor. A second movable barrel is attached to the interior of the first movable barrel. The second movable barrel does not rotate, but goes straight along the optical path together with the first movable barrel. Inside the second movable barrel, is rotatably attached a lens turret in which a plurality of lenses are concentrically arranged. The lens turret is intermittently rotated in accordance with a rotation of the first movable barrel to set one of the lenses at the optical path. Each lens is set to the optical path at a position where back focus is taken into consideration, so that a focal length of a taking lens is changed. When the lens turret goes straight together with the second movable barrel without rotating, focusing is performed at the set focal length. A magnification of a viewfinder optical system is changed in association with a rotation of the lens turret.