A lens unit of the present invention has a mounting cradle, a lens frame holding portion fixed to a mounting cradle in an optical axis direction, a lens frame which is held to the lens frame holding portion to be capable of moving to the optical axis direction, and a lens group fixed to the lens frame. The lens unit further has an adjusting screw provided parallel with the optical axis direction, a nut which is provided to the adjusting screw and whose position with respect to the mounting cradle is fixed, a cam portion which is fixed to the lens frame and is engaged with the adjusting screw, and a switching lever which is provided between the nut and the cam portion so as to be capable of rotationally moving about the adjusting screw, on the outside of the lens frame holding portion. A position of the lens frame in the optical axis direction is switched between a standard photographing position and a micro photographing position by rotational movement of the switching lever.