Patent ID: 7085486

Claim:
A lens barrel including a rotatable ring rotatable about a rotational axis extending in a direction of an optical axis, an outer annular member which is non-rotatable and supports said rotatable ring inside said outer annular member, and at least one optical element movable along said optical axis by a rotation of said rotatable ring, said lens barrel comprising: an advancing/retracting mechanism, provided between an outer peripheral surface of said rotatable ring and an inner peripheral surface of said outer annular member, configured to move said rotatable ring along said optical axis between front and rear movement limits of said rotatable ring in said optical axis direction relative to said outer annular member, when said rotatable ring is rotated; at least one circumferential groove located on one of said inner peripheral surface of said outer annular member and said outer peripheral surface of said rotatable ring; and at least one rotation-guiding projection located on the other of said inner peripheral surface of said outer annular member and said outer peripheral surface of said rotatable ring, wherein said at least one rotation-guiding projection is engaged in said at least one circumferential groove such that said rotatable ring is rotatable at an axial fixed position without moving along said optical axis when said rotatable ring is moved to said front movement limit by said advancing/retracting mechanism.