In a lens barrier device, one barrier blade is arranged at a different height in the optical axis direction from another barrier blade, and a barrier base is provided with a regulating portion which is at the outer peripheral portion of an optical axis forward end side barrier blade and which regulates the position in the optical direction of the optical axis forward end side barrier blade, thus forming the lens barrier device as a unit. If rotation shafts for the barrier blades are formed on an external cover, deformation or the like would be generated when the external cover is assembled to the apparatus, resulting in an increase in the requisite drive force for the opening/closing operation. Hence, it is possible to prevent a suitable opening/closing operation from being hindered by such an increase in the requisite drive force.