A lens barrel extending and retracting mechanism. A photographic optical axis and a central axis of a lens barrel are eccentric such that a first lens group and a second lens group are housed in a side of a CCD separated from the optical axis. The lens barrel is rotatably extended around the central axis thereof, and a picture is taken when lens optical axes of the first lens group and the second lens group coincide with the optical axis. The lens barrel extending and retracting mechanism prevents displacement and tilt of the lens optical axes of the first lens group and the second lens group, maintaining optical performance and reducing the size of the lens barrel in the housed position.