The 3D computer graphics (3D-CG) animation using a virtual actor's speaking is very effective as an educational medium. But it takes a long time to produce a 3D-CG animation. To reduce the cost of producing 3D-CG educational contents and improve the capability of the education system, we have developed a new education system using Virtual Actor. It includes a 3D-CG stage, many kinds of stage parts (3D-CG shaped models, photographs or text panels) and Virtual Actor(s). Virtual Actor is a software robot of various shapes based on 3D-CG and speech synthesis. Virtual Actor speaks English/Japanese by voice synthesizer with facial expressions and body actions. We have developed two kinds of education system, one is a Cyber Assistant Professor (CAP) and another is a Cyber Theater (CT). CAP has been designed for a self-learning system, which enables interactive communication between Virtual Teacher and learner. CT has been designed for a 3D-CG story maker, which is a new 3D-CG media player, attractive enough to arouse the pupil's interest. We also have developed the exclusive scenario language to write a scenario of 3D-CG animation. It is a tag-based hypertext language like HTML. Both CAP and CT convert this scenario to real-time interactive 3D-CG animations, which are not rendering movies. This paper describes the system architecture of CAP and CT, details of scenario language and results of experimental lessons. (Contains 5 tables and 16 figures.)