Patent ID: 8075206

Claim:
A lens barrel comprising: a fixed cylinder; a first rotating cylinder which is placed to be rotatable around an axis to the fixed cylinder; a linear movement cylinder in a cylindrical shape which is placed in an inner circumferential side of the first rotating cylinder and moves integrally in an axis direction with the first rotating cylinder and rotates relatively around the axis; and a second rotating cylinder which is placed in an inner circumferential side of the linear movement cylinder, wherein the linear movement cylinder has three or more projections which are projected outside in a radius direction in an outer circumferential surface, the first rotating cylinder has three or more cutouts in the inner circumferential surface thereof, the three or more cutouts corresponding to each projection of the linear movement cylinder and a shape of the cutouts corresponding to a shape of each projection, and the three or more cutouts of the first rotating cylinder are respectively formed in parallel with an axis of the first rotating cylinder and in which each projection of the linear movement cylinder is inserted, wherein an end of each cutout in which each projection is inserted is extended to a groove in a circumferential direction, and each projection is guided in this groove in the circumferential direction, and the first rotating cylinder and the linear movement cylinder are connected, wherein the linear movement cylinder has a through-hole to a pin provided in the second rotating cylinder, and wherein at least two of the three or more projections are placed in an area in a circumferential wall of the linear movement cylinder where the through-hole is not formed in the circumferential direction.