Patent ID: 7864241

Claim:
A lens barrel, in which at least one portion of a plurality of lens groups is collapsed to store the plurality of lens groups in a collapsed state and at least one portion of the plurality of lens groups is moved toward an object in a photographing state, the lens barrel comprising: a lens frame retaining at least one portion of the plurality of lens groups; a first lens cylinder supporting the lens frame inside thereof and including a plurality of cam followers on an outer circumferential section thereof; and a second lens cylinder including a mutually parallel plurality of cam grooves in an inner circumferential section thereof and storing the first lens cylinder therein in the collapsed state, the plurality of cam grooves being engaged with the plurality of cam followers and configured to advance and retire the first lens cylinder in a direction of an optical axis by a relative rotation of the first lens cylinder, wherein the plurality of cam grooves have two first cam grooves and two second cam grooves, the plurality of cam followers have two first cam followers and two second cam followers, the two first cam followers and the two second cam followers being engaged with the two first cam grooves and the two second cam grooves, respectively, and wherein the two first cam followers are disposed at positions different from each other circumferentially at substantially 180 degrees, the two second cam followers are disposed at positions different from each other circumferentially at substantially 180 degrees, the two first cam followers and the two second cam followers being circumferentially and alternately disposed at intervals close to even intervals, and the two first cam followers and the two second cam followers are spaced apart by a predetermined distance in the optical axis direction.