Saiichiro UCHIMARU (1877-1969) was the professor of Tokyo Imperial University. He had written many mechanical engineering books during from the late Meiji Era to the middle of Showa Era. These nine books on heat engine or fluid machinery were generally read by not only students but also many engineers. As a result, he contributed greatly to progress of mechanical engineering education of Japan. This paper describes his personal history and achievements in activity of writing books.