To improve the courses of computer-based education in junior high school and high school, we have developed new educational multi-media tool, named Cyber Theater. Cyber Theater provides the capability of easy making the 3D-CG animation that includes the sound effect, background music and Virtual Actor's speaking by speech synthesizer. The scenario of animation story is written by Script language named CTSL (Cyber Theater Scenario Language). CTSL is a Tag-based hypertext language, which can describe the scenario of 3D-CG animation story easily. We also have designed the Creative Lesson, where pupils studied how to make a 3D-CG animation by using CTSL and produced their original animation as their short presentation. The main subject of this lesson is to teach pupils that a computer is not only a tool for browsing information, but also a tool for creating the information. Pupils have created the 3D-CG animation of complex presentations or stories with clear sense of purpose. For Cr...