Abstract: A lens barrel includes a straight-moving cylinder including a lens group therein, being movable in a direction of an optical axis of the lens group without being rotated, and having a depression on a posterior end portion of the straight-moving cylinder; a guide pin protruding from the outer circumferential surface of the straight-moving cylinder; a rotational-moving cylinder movable in the direction of the optical axis, having a cam groove for engaging with the guide pin); and a reinforcement pin projecting from the inner circumferential surface of the rotational-moving cylinder; wherein the depression includes a contact surface separated from a side portion of the reinforcement pin with a predetermined clearance.

Abstract: A lens barrel comprising (4): a straight-moving cylinder (21) including a lens group (10) therein, being movable in a direction of an optical axis of the lens group (10) without being rotated, and having a depression (43) on a posterior end portion of the straight-moving cylinder (21); a guide pin (39) protruding from the outer circumferential surface of the straight-moving cylinder (21); a rotational-moving cylinder (18) movable in the direction of the optical axis, having a cam groove (40) for engaging with the guide pin (39); and a reinforcement pin (41) projecting from the inner circumferential surface of the rotational-moving cylinder (18); wherein the depression (43) includes a contact surface (42) separated from a side portion of the reinforcement pin (41) with a predetermined clearance (d).