A lens barrier for opening and closing a lens opening of a lens barrel, including a plurality of barrier plates which are spaced from one another in the direction of their thickness so as to slide in a direction perpendicular to the optical axis of the lens opening. A barrier driving mechanism is provided which moves the barrier blades between an open position in which the barrier blades are superimposed on one another outside the lens opening and a closed portion in which the barrier blades are located side by side in the lens opening to close the latter.