This study revealed that Mr. Suzuki has changed his teaching style into a teaching structure from the pupils’ side, learning from his daily in his teaching practices, and changed his teaching materials, organization of teaching process, learning style/learning activity all together. The reasons why Mr. Suzuki succeeded are because he made it possible for the pupils to think the learning theme that the teacher has set as their own learning theme, and because he changed the learning theme into the learning process that the pupils pursue, while paying attention to pupils’ inner world and thoughts. It is considered that the facts that he created his teaching theory elaborately and firmly while correcting and reorganizing his teaching structure through his practice may give suggestions to develop the quality of in-service teachers.