In this paper, diversity of agricultural production and its change was examined for some 45 years in Japan and for 1960, 1980, and 2000 in Tottori prefecture. The concept of entropy was used in order to measure the diversity of the agricultural production which consists of some sections. Agricultural production section in Japan has been diversified in the long run. The ratio of rice has been decreasing gradually for a policy of cutting back on the acreage under cultivation. Although the ratio of stock raising and fruits has increased, it tends in recent years to stagnate. The rate of vegetables has increased remarkably. Combination type for every municipalities was determined with the standard value A method, and complemented examination of agricultural diversity.