Patent ID: 8355212

Claim:
A lens unit comprising: a lens holding frame which holds a lens element; a fixed cylinder formed with an oblong hole in one lateral surface thereof, the oblong hole extending in a direction of an optical axis of the lens unit; a cam cylinder moveable in the optical axis direction and rotatably held in the fixed cylinder, the cam cylinder including a gear portion on an outer surface of a base end thereof to drive the lens holding frame in the optical axis direction; a major axis gear having such a length in the optical axis direction as to be received in the oblong hole, the major axis gear being engageable with the gear portion of the cam cylinder; a driving member which rotates the major axis gear by way of a plurality of gears; and a pressing member provided on an end surface of the major axis gear, and adapted to press the major axis gear in the optical axis direction, and structured to generate a friction force on the end surface of the major axis gear, wherein the friction force prevents a free movement of the cam cylinder when the lens unit is directed upwardly or downwardly, and allows a movement of the lens holding frame in the optical axis direction when the driving member rotates the major axis gear by way of the plurality of gears.