A first moving state at a given time including any of a position, a velocity, and a moving direction of a moving object moving in a space is estimated. A constraint condition for calculating a second moving state at the given time is set using the first moving state and a previously-calculated second moving state including any of a position, a velocity, and a moving direction of the moving object moving in the space. The first moving state is corrected using the constraint condition to calculate the second moving state at the given time.