An input motion acquiring unit acquires a motion trajectory of an object from an image recognizing unit. A dynamic modelling processor models a plurality of robot motion patterns stored in a robot motion pattern storage unit in a dynamic system form, and stores the modelled robot motion patterns into a robot-motion-pattern-model storage unit. A motion converting unit linearly transforms the plurality of robot motion dynamic models stored in the robot-motion-pattern-model storage unit into prediction motion trajectories. A motion comparing unit compares the input motion trajectory acquired by the motion acquiring unit with the prediction motion trajectories transformed by the motion converting unit. A robot motion selecting unit selects a robot motion pattern having the highest similarity from the robot motion pattern storage unit.