A lens barrel includes a fixed portion with an optical system including a focusing lens. An operation member is placed so as to be movable to first and second positions along an optical axis of the fixed portion, and turnable around the optical axis at the first and second positions. A turning member turns along with the operation member when moved to the second position, and does not operate with the operation member when moved from the second position to the first position. Positioning means position the operation member at the first or second position through a plurality of balls. When the operation member is at the first position it is urged to the first position by the plurality of balls. When the operation member is at the second position, it is urged to the second position by the plurality of balls.