In a lens barrel including an image pickup optical system containing plural lens groups and a barrel member for holding the image pickup optical system and conducting protruding and retracting, the lens frame holding a prescribed lens group of the image pickup optical system is swung so that the prescribed lens group is moved to a position where the optical axis is different from those of other lens groups at the time of the retraction, and in the process of changing from the protruded state to retracted state, the lens frame is swung by engagement with a cam-shaped portion of a first engagement member, and is then engaged with a second engagement member.