The utility model provides a multiplying power auto -change over device and digit section scanner. Multiplying power auto -change over device utilizes the rotatory driven part of step motor or servo motor drive, and step motor or servo motor receive the control of the signal of telecommunication, can realize accurate angle displacement, therefore also can realize accurate angle displacement by step motor driven synchronizing shaft, furtherly, and the switching of rotatory driven part between a step motor 0 and the 2nd step motor 0 will be very accurate, can switch over step motor 2 accurately. In addition, controller and step motor's application with the simplification that becomes of loaded down with trivial details multiplying power switching process, can promote work efficiency. Step motor's use is also more stable than traditional manual operation. Digit section scanner includes above -mentioned multiplying power auto -change over device, utilizes the rotatory driven part of step motor or servo motor drive, also has accuracy, stability, conveniently switches the magnification's advantage.