Abstract: A direction input device and a method for operating a user interface using the same are disclosed. The direction input device, according to one embodiment of the present invention, comprises: a pad which includes, on one surface thereof, a marked surface having marks with different codes according to each mark, or which is integrated with the marked surface; an optical unit which is physically connected to the pad in the direction of the marked surface of the pad, irradiates the marked surface of the pad with light through a light source, senses light reflected from a predetermined mark on the marked surface through a sensor when a user force is applied, and converts the light into an image signal; and a connecting unit for connecting the pad and the optical unit.