A lens barrel that is capable of decreasing a barrel length under a retracted condition by simplifying a configuration. The lens barrel changes a focal length by moving first and second lens groups in an optical axis direction. A light-amount adjusting member is located between the first and second lens groups. First, second, third holding frames hold the first lens group, the second lens group, and the light-amount adjusting member, respectively. A cam mechanism moves the first, second, and third holding frames in the optical axis direction so that a part of the second lens group is inserted into the aperture of the light-amount adjusting member and concave and convex surfaces of the first and second lens groups are overlapped in the optical axis direction under a retracted condition. The aperture diameter of the light-amount adjusting member is enlarged when shifting to the retracted condition from a shooting condition.