To provide a zoom lens driving device for a 3D camera capable of accurately alinging right and left focal distances by setting either of right and left zoom lenses as a master side and the other as a slave side and allowing a variable power lens on the slave side to follow the movement of a variable power lens on the master side.

Either zoom lens (master side) 10 out of two zoom lenses 10 and 20 arranged to be paired right and left directly controls a motor driver 64 by the operation of a zoom switch 36 so as to drive the variable power lens 12 in a telephoto direction or a wide direction. The other zoom lens (slave side) 20 controls a motor driver 74 by the use of a control signal in response to zoom position error voltage (voltage showing positional error between the variable power lenses 12 and 22) generated by a differential amplifier 30 and a comparator 32, so that the 2nd variable power lens 22 is driven in a direction where the error becomes small.