Secular trends for speedier growth and greater adult size exist among the Japanese as they do among many other peoples. By using data colleted annually by the Ministry of Education, it is possible to transform cross-sectional data into longitudinal form. This is displayed by a graphic method which permits us to observe the relationship between the two secular trends. It is found that both menarche and the period of maximum growth velocity are now a year earlier than they were during the first decade of the twentieth century. Adult height, both for students and the entire population, has increased steadily (except for the period of the war) during the present century; and, to a lesser extent, weight has increased.