1. A 3-dimensional tracking system, comprising: a photographing unit for photographing an object; a recognizing unit for recognizing a marker attached to the object by binarizing an image of the object photographed by the photographing unit; an extracting unit for extracting a 2-dimensional coordinate of the marker recognized by the recognizing unit; and a calculating unit for calculating a 3-dimensional coordinate from the 2-dimensional coordinate of the marker by using an intrinsic parameter of the photographing unit, wherein the object is a rod-shaped instrument; and wherein the calculating unit calculates a 3-dimensional coordinate from 2-dimensional coordinates of three or more markers attached to the object, wherein the object is a rod-shaped instrument having pincers attached to one end thereof, and wherein the calculating unit further calculates shape change of the pincers by using the difference in distance according to movement of a movable marker attached to the pincers with respect to a criterion marker attached to the object.