1 such that turning spur gears 12 causes optics tube assemblies 1 to turn the angular positions of the two offset spur gears 12 are precisely matched during the assembly process and fixed to optics tube assemblies 1 so as to establish and maintain the relationship of the two fields of view 14 provided by the two optics tube assemblies 1 as also seen in fig3 two bearing sleeves 15 each featuring annular grooves are also fixed to optics tube assemblies 1 bearing sleeves 15 are fixed to optics tube assemblies 1 so as to be equidistant from the distal ends of the optics tube assemblies 1 fig4 shows further elements of the actuating mechanism contained within body 5 of stereoscopic endoscope 100 more particularly the actuating elements contained within body 5 of stereo endoscope 100 comprise a ring gear 16 which engages the two spur gears 12 this gear train i e the two spur gears 12 and ring gear 16 is designed to provide two revolutions of spur gears 12 to each revolution of ring gear 16 ring gear 16 is secured to a face cam 17 face cam 17 is contoured to provide one complete proximal distal reciprocating excursion of optical tube assemblies 1 for each complete revolution of their respective spur gears 12 as will hereinafter be discussed in addition the timing of face cam 17 to the gear train i e to the two spur gears 12 and ring gear 16 is such.