To solve the problem that a barrel structure is made multiplexed/complicated to induce enlargement of a lens barrel and increase of parts count especially in the case of an inner focus system.
The lens barrel has a lens holding cylinder 8 for holding a lens 11, a cam cylinder 7 which is provided on the outside in the diametrical direction of the lens holding barrel so as to be able to rotate around an optical axis and has a cam part for driving the lens holding cylinder in the direction of the optical axis, provided on an inner circumferential surface thereof, a rotating cylinder 5 which is provided on the outside in the diametral direction of the cam cylinder rotatably around the optical axis and is engaged with the cam cylinder to transmit torque to the cam cylinder, and a fixed cylinder 1 which is provided on the outside in the diametral direction of the rotating cylinder and has a cam part for driving the rotating cam cylinder in the direction of the optical axis, provided on an inner circumferential surface thereof. Engaging parts 7b and 7f provided on the outer circumferential surface of the cam cylinder are engaged with a guide part 5d which is provided on the rotating cylinder and is extended in the direction of the optical axis, and the cam part provided on the fixed cylinder 1.
KOYAMA ATSUSHI
Atsushi Mizumoto
Hiroji Obana