Fuku–Ō--Yukichi Fukuzawa (1835 ~1901), a venerable great man was not only an Enlightener, an Educator and a Journalist but also the Originator of Keiō–Gijuku of Meiji Era of Japan. As to the conceptualism of Fuku–Ō’s Civilization, it would be throughly grasped in his great work of Bunmeiron–no–Gairyaku. In his work, Fuku–Ō emphasized that the sole standard of planning and satisfying Japanese modernization and needs is Western Civilization and real world situations. And only things that were related to the real world situations and aimed to fulfill the Western Civilization could be regarded as “Advanced ”. The objective of this study is focused upon analyzing Fuku–Ō’s following four different phases : Material & Immaterial Culture, Rationalism & Individuality, Civilized Realism, and Enlightening Movement. In reviewing the developing track of Post–Meiji Era of Japan, one certainly could attribute the successfulness of modern Japanese Life Rationalization, Modernization and Elevation to the great work of Fuku–Ō, which should be actualized duing the scientific spirit.