A lens barrel comprises a first frame including an inward flange having an
opening as a light path for a photographic optical system, a
barrier-driving member disposed in the vicinity of the opening, a second
frame disposed inside the first frame and movable along an optical axis
relative to the first frame, a barrier blade movable along with the
rotation of the barrier-driving member between a closed position in which
the barrier blade blocks at least a part of the light path and an open
position in which the barrier blade is retracted from the light path, an
opening-urging member capable of urging the barrier blade towards the
open position and urging the barrier-driving member towards a first
direction, and a closing-urging member capable of urging the barrier
blade toward the closed position.