A lens barrel unit including a lens barrel which has a plurality of lens groups and is set to a photographing state by moving at least a part of the lens groups to an object side and to a collapsed state by moving the at least the part of the lens groups to an image plane side and storing the lens groups, the lens barrel unit includes: a first supporting frame which retains at least one lens group of the lens groups; a second supporting frame which retains the first supporting frame movably in an optical axis direction of the lens barrel; a first supporting frame moving section which moves the first supporting frame in the optical axis direction of the lens barrel; and a fixed cylinder in which a main shaft which is capable of moving the second supporting frame in the optical axis direction of the lens barrel is provided.