1. A motion capture apparatus for tracking three-dimensional positions and postures of joints, and limbs of an objective person, said motion capture apparatus comprising: generating means for generating a kinematics model having joints connected to one another from an observation image of said objective person; predicting means for hierarchically calculating predicted positions at a current time of the joints of said objective person in accordance with a constraint of coupling among the joints and predicted positions at a preceding time of the joints in said kinematics model, and predicting three-dimensional positions and pastures of the joints and said limbs of said objective person at the current time; projecting means for projecting the three-dimensional positions and postures of the joints and the limbs of objective person at the current time on a two-dimensional image plane, the three-dimensional positions and postures being predicted by said predicting means; evaluating means for evaluating reliability about projection positions projected by said projecting means in accordance with the observation image of said objective person; and estimating means for estimating the three-dimensional positions and postures of the joints and the limbs of objective person at said current time in accordance with an evaluation result about said reliability.