The concept of religion is classified into religion as theory and religion as practices, and likewise that of education into education as theory and education as practices. Religious education is understood as religion-oriented one and education-oriented one. Religious education has been exercised as religion-oriented one under the name of ``education for religion``. Here religion and education were likely to refer those as practices. Therefore, this kind of religion-oriented religious education at school cannot but face the conflicts among religions, which might result in the political compromise making students choose a religious instruction among several ones or making religious education deal with understanding about general religion. In education-oriented religious education, however, the conflicts among religions might be resolved in that religion would be regarded as subject matter for educational experiences, shown by the endogenous theory of education. According to religious theory, religion is to be understood not only as a transcendental phenomenon paying attention to the absolute truth but as spiritual discipline toward continuous growth. Religious education can be facilitated by taking into account both religion-oriented and education-oriented religious education. This is closely related to the development of educational studies as well as religious studies responsible for exploring education and religion as theory.