1. An apparatus for tracking a position, comprising: a depth image obtaining unit configured to obtain a depth image; a feature extracting unit configured to receive the depth image from the depth image obtaining unit and extract features for each pixel from the received depth image to generate a feature set for each part of a human body; a classifier training unit configured to train a classifier, which distinguishes a position of each part of the human body, by using the feature set generated in the feature extracting unit; and a position determining unit configured to extract features of each pixel from the depth image received at the depth image obtaining unit in a state in which the classifier is trained by the classifier training unit, distinguish a body part of each pixel through the trained classifier, and track three-dimensional position information of each body part.