To control a controlled system very precisely by driving it by a small- sized stepping motor in the limited space of a video camera or the like and generating no deviation between the controlled system and stepping motor.

The controller for the lens driving system which brings the stepping motor under feedback control has the zoom motor 13 of the stepping motor driving a zoom lens 7, a motor driver 14, a zoom reset sensor 11 which detects the reference position of the zoom lens 7, a magneto-resistance effect sensor (MR sensor) 9 which detects the current position of the zoom lens 7, a detecting circuit 8, and a zoom control part 21. Then the zoom control part 21 outputs a control signal for the zoom lens 7 to the motor driver 14 by referring to a zoom lens operation switch, the reference position detection signal of the zoom reset sensor 11, and the current position detection signal of the zoom lens 7 from the detecting circuit 18 to drive the zoom motor 13. The zoom control part 21 judges whether or not the zoom motor 13 operates exactly according to the control command.