In the recent world situation, our way of life has been drastically changing due to the remarkable development of technology, evolution of AI, and pandemics caused by a new type of coronavirus. In order for our students to survive in this changing environment, we need to change the way education is provided, so that students can acquire the newly required skills and adapt to the coming age. To this end, teachers are required to improve their classes so that the learning process becomes more fulfilling. This is also stated in the new Courses of Study announced for 20191. In Japan, from the viewpoint of "what is to be learned," classes have traditionally been taught mainly in a teaching-intensive manner. However, as mentioned above, education needs to be transformed in accordance with the changing times. This transformation of education is a departure from the traditional teaching-intensive classes, and classes that are conscious of proactive, interactive, and authentic learning (active learning). Therefore, it is an important issue for teachers to be able to acquire the ability to conduct such classes2. The research team led by Dr. Tosa conducts research on active learning3 and is developing an avatar class program suited to the Japanese educational format, based on the "Teaching Avatar Program" that is being tried in Florida, USA. In this avatar space, lessons are given to students, and teachers can practice their lessons. This is an advanced attempt in this day and age of communication technology in the avatar space. As a test subject, I experienced the Law of Conservation of Mass lesson program. I discussed with other participants the insights and transformations I gained from this experience, and clarified the outcomes and challenges. This presentation will report on the outcomes and challenges, as well as the usefulness and future potential of the program. In addition, as a member of the team, I plan to develop a classroom program in the field of biology in the future. [1]Courses of Study, [2]Central Council for Education, [3]Dr. Tosa. (2018). Physics Education (Journal of the Japan Society for Physics Education), 66(2), 144-147.doi: 10.20653