Recently, the development of the micro-computer has been remarkable. Many techniques that were impossible a few years ago are now possible. Superimposition is one of those techniques. Meanwhile, many visual teaching materials have been developed, for example video tapes and micro-computers, but teachers are not yet prepared to make a good use of them. This letter describes applications to audiovisual instruction by video superimposition using a microcomputer. In this system, as well as video aids can be used. This letter show four examples that are supported by video superimposition using a micro-computer. It is concluded that superimposition by a micro-computer is extremely useful for audiovisual instruction. This system is inexpensive, quite simple, and useful even with only a little knowledge of programming. The superimposition system is helpful not only if used by teachers but also if used directly by students.