本論文は、同じ自民党出身の首相であるにもかかわらず、靖国神社参拝問題においては対応上の違いが現れる理由に問題意識を持ち、靖国神社参拝問題に対する首相の決定に影響を与える要因を安倍、菅、岸田首相を事例として明らかにしようとした。 分析においては、安倍、菅、岸田首相の参拝行動を個人的背景要因、国内政治的要因、国際体制的要因を通じて比較分析してみた。 分析の結果、安倍首相の靖国神社直接参拝には個人的な背景要因と国内政治要因が作用したことが分かった。一方、菅と岸田首相の供物奉納には国内政治要因のうち総裁選挙との関係が高いことが分かった。最後に、参拝自制の要因としては、国際体制要因の中で日米関係が共通して作用したが、東アジアへの米国の関与が高まると、首相の靖国神社参拝が抑制されることが明らかになった。

This paper questions why only certain Prime Ministers of the Liberal Democratic Party insist on visiting the Yasukuni Shrine, and attempted to analyze the factors behind the Prime Minister's decision to visit the Yasukuni Shrine. In the analysis, the framework of level of analysis and factor analysis was used to identify the multi-layered factors that influence the Prime Minister's decision to visit the shrine, and to compare the influence between factors. The shrine visitation behavior of three prime ministers was comparatively analyzed through personal background factors, domestic political factors, and international system factors. As a result of the analysis, it was found that personal background factors and domestic political factors played a role in Prime Minister Abe's direct visit to Yasukuni Shrine. Meanwhile, Suga Kishida's tribute offering was found to be highly related to the presidential election among domestic political factors. Lastly, among the factors in the international system, the U.S.-Japan relationship was a common factor in refraining from visiting the shrine, and it was clearly shown that when the U.S. involvement in East Asia increased, the Prime Minister's visit to the Yasukuni Shrine was suppressed.