A game device models images of moving images such as motor-bikes or cars moving through a virtual space. The track along which a first such moving object moving through the virtual space is sampled at a prescribed interval in time in order to generate track data P₁-P₆, while transit points P₁-P₆ are set at prescribed intervals of distance along the track indicated by the track data. A second moving object is moved in such a manner as to pass through these transit points. Accordingly, a course is set that is commensurate with the player's skill level so that the degree of difficulty of the game is not diminished by the degree of experience of the player.