It is generally assumed that a good theory of education depends upon a healthy theory of human being. The teacher usually has his own conception of man whether or not he is aware of it which ultimately guides his educating: he tries to help his students to become such a person as his conception of man, of which he thinks healthy and desirable. The criterion of which theory of man is good depends upon the fact that the closer the theory is to the reality of man, the better it is. Man lives-in-the-world: he cannot exist without the world: Neither can he be separated from the world. Dewey undercuts the dichotomy between man and the world with his formulation of “organism-environment transaction,” whereas Heidegger does that with his formulation of “Being-in-the-world” as both hyphenated. For Heidegger, man simultaneously lives in Eigenwelt, Mitwelt, and Umweit. All three horizens of being-in-the-world, neither one of which is prior to the other, continually disclose themselves in lived experience. However, for Dewey cannot find Eigenwelt and Mitwelt in his world of “organismenvirornment transation.” It is because Dewey sees man without, whereas Heidegger within, in which fear and trembling occurs. Dewey concerns with the experiences between man and environment, whereas Heid egger concerns with the immediate experiences which reveal themselves to the human consciousness only. Therefore, it is very difficult to accomadate Dewey’s conception of man for the education of “becoming-a-person.” Dewey’s conception of environment, however, gives much power to the development of theories of education in terms of society and culture. 1. As we need eyes to see and ears to hear, so do we Dewey’s experience “out-there” and Heidegger’s immediate experience as viewed from “within” in order to understand human being as he is. 2. For education, we need both methods of science and phenomenology, because environmental forces can be best handled through the empirical method of science, whereas the lived experience of the student can be revealed through a phenomenological method. 3. For the education of intelligence, Dewey’s scieuitific method is needed. However, for the education of self-awareness an existential-phenomenological approach gives much insight. 4. “Choosing” in our life is very important. Dewey's choice based upon intelligent, rational, and scientific appraisal of the consequences is needed in any kind of education, whereas choice based upon risking oneself for, and committing oneself to, an idea or ideal which is larger than oneself is, too, needed for the education of authenticity. 5. Dewey’s “habit” is very important for the student to adjust to his environment, likewise Heidegger’s “self-transcendence” is important for the student to be able to ask "Who am I?" which is only possible to be asked by the unique human being. 6. For the development of human being, the teacher should be concerned about both the individuality and the society including culture.