二次大戰後對於如何排除神道對國家、社會、學校教育之影響，成為確保民主、自由、人權所必須面臨的挑戰。因此日本憲法除了保障宗教自由之外，更特別列入政教分離原則，以徹底瓦解神道對宗教信仰的獨佔地位。日本國憲法第二十條與第八十九條所規範的政教分離包含以下三點：（1）禁止宗教與政治力結合，（2）國家權力不可介入任何宗教色彩，（3）國家財政資源不得提供或援助宗教活動。 另外，有關政教分離原則亦涉及宗教活動與政治活動之間應如何界限的種種爭議。例如，以某一特定宗教團體信徒為主所組成的公明黨，是否違反憲法政教分離原則；首相及政府官員到靖國神社祭拜是否違憲；公共建築物的開工典禮中，舉行傳統神道儀式是否違憲等爭議及判決法理之研究則往往成為爭議的焦點。 據此，本論文係以歷史的角度來審視國家與宗教之間的關係，以了解其產生衝突與結合之原因，並進而闡述政教分離概念的形成與發展，乃至於成為法制層面保障的進程，並藉此以了解日本國憲法中政教分離原則規定之法條構造背後的法理基礎與進行違憲審查之際的判斷準據。 After World War II, how to remove Shinto’s influence on the country, society and education was an acid test for ensuring the democracy, freedom and human rights. Therefore the Constitutional Law of Japan not only ensured the freedom of religion but also defined the separation of state and religion statutorily, in order to abolish the unity of government and ritual system. Article 20 and article 89 of the Constitutional Law of Japan regulate the separation of state and religion which included the three points:（1）religion which combined with political power was impermissible;（2）national power can not carry any religious color;（3）financial resources of the country can not provide or aid any religious activities. Besides, the separation of state and religion also involved in that how to define the boundary between religious activities and political activities. For example, if hold traditional Shinto ceremony in the beginning of the public buildings’ work violating the constitution? The Study of these disputes and the legal principle theory of law of court decisions often became our focal points. So, this thesis examined the relations between nation and religion by historical angle and tried to understand the reason of their conflict and coalition. Then it described the formation and the development of the separation of state and religion conception. Finally, it tried to understand the legal principle theory of law behind the separation of state and religion article of the Constitutional Law of Japan, and check the judgment datum of judicial review.