Abstract: An actor management section (110) manages the generation, activation, execution per unit time, sleep, halt, restart and termination of actors (20) to (40) which are instances of a class and are also processes that can be executed in parallel and generates images such as those of a character (42), a stage (44), and an egg (46) which are each represented by these actors. Actors also include sound control actors, storage region management actors, and actor-to-actor communications actors. Each actor is managed on the basis of actor information stored in an actor structure. Details such as member variables and methods for each actor are described in scripts, and scripts, models, and disposition information can be combined and freely modified in real time. The execution code of a script used in common by a plurality of actors is stored in the same storage region. Using a shell, an operator can control actors interactively.