LENS BARREL

PROBLEM TO BE SOLVED: To provide a collapsible lens barrel capable of precisely positioning a lens while preventing unnecessary light beam from being generated from an opening formed in a lens holding member.SOLUTION: The lens barrel according to the invention holds plural lenses and is arranged to change between an extension state in which all of the lenses are disposed on an optical axis and a collapsed state in which a retreat lens in the lenses is retreated from the optical axis to reduce the length thereof. The lens barrel comprises: a holding member having an opening; a retreat lens frame that holds the retreat lens, and that is positioned in an area overlapped with the opening in the extension state and retreats from the opening in the collapsed state; and a light shielding blade that is disposed between the holding member and the retreat lens frame and shields an area not overlapped with the retreat lens frame positioned in the opening in the extension state and retreats from the opening in the collapsed state.