contacts 41 and 42 of a zoom control switch 40 on the outer surface of the fixed tube 21 and therefrom to the aforesaid interconnection terminal 33 so that the outer coil 36 is supplied with current from the power source in the camera body the aforesaid zoom sleeve 34 is slidably fitted in the inner diameter of the fixed tube 21 and fixedly carries two zoom lenses l1 and l3 and a diaphragm device 43 a roller 44 on the outer surface of the zoom sleeve 34 is in engagement with a cam groove 21a formed in fixed tube 21 a lens holding tube 45 which holds a compensator lens l2 positioned between the zoom lenses l1 and l3 is fitted in the inside of said zoom sleeve 34 a roller 46 threadedly held on the outer surface of lens holding tube 45 extends through a cam groove 34a formed in the zoom sleeve 34 and comes into engagement with a cam groove 21b formed in the inner surface of the fixed tube 21 the zoom control switch 40 has a tumbler type change over switch which is so arranged that when it is pushed down at one end 40a for telephoto the switch 40 closes its contact 41.