A lens barrel includes a light amount adjuster including a shutter to open an opening portion of a lens system upon non-shooting and which can be moved in the optical axis direction of the lens system, an adjacent member having an optical element adjacent to the light amount adjuster so as to become movable relative to the optical axis direction and which can be inserted into the opening portion and a space restricting member interposed between the light amount adjuster and the adjacent member and which prevents the optical element from being inserted into the opening portion upon shooting.