政黨輪替是當代民主政治發展的重要條件。日本的民主政治雖然在戰後 新憲法公布後即開始進行，但自1955 年起便形成自民黨一黨獨大的政治體 制。這是因為，日本戰後的政黨輪替思維，受限於國內政治、經濟、社會與 政黨條件等國內外環境的影響，使其無法在民主政治發展過程中具體展現。 冷戰結束後政經情勢的轉變，讓日本的政黨輪替思維獲得解放，也促成了日 本民主黨的成立與發展。本文主旨是藉由民主理論與近代日本政治發展觀 點，思考政黨輪替思維在日本的演變歷程，並以日本民主黨的成立背景、組 織發展來分析其在政黨輪替思維演變中的角色與定位。

Party alternation is an important condition for the development of modern democracy. Although the Japanese democracy after World War II proceeded from the enforcement of the new constitution, LDP dominated the Japanese politics since 1955. The party alternation thinking in Japan was limited by the situations of domestic and international environment such as politics, economics, society and parties. The end of the Cold War liberated the party alternation thinking in Japan, and led to the formation and development of DPJ. This paper aims at the changes of party alternation thinking in Japan based upon the theories of democracy, as well as the aspect of Japanese political development. Furthermore, the roles of DPJ in the development of party alternation thinking in Japan were also proposed in this paper.