A lens driving device is based on a Voice Coil Actuator (VCA) structure and provides the auto-focusing and optical image stabilization (OIS) functions. These two functions can be realized by a common magnet scheme, or a separate magnet scheme. Also, the present invention provides an improved structure for the lens driving device to enhance the function of OIS thereof. By arranging a magnetic enhancement device below the OIS coils in the lens driving device, the magnetic driving force of the OIS coils and magnetic induction of the Hall sensors, if present, can be enhanced, and the magnetic sensitivity thereof may be also improved.