歐洲聯盟之成立使歐洲統合進一步深化與廣化。隨著會員國移轉更多主權予歐洲共同體，而部長理事會議事程序引進更多條件多數決，使得不經全體會員國同意的議案亦能通過，其決議卻影響到廣大歐洲人民之經濟社會生活，會員國及其人民對權力不斷擴展的歐洲聯盟充滿疑慮，對統合速度加快不斷侵蝕會員國主權滿懷恐懼。歐洲聯盟為了維持共同體與會員國間的權力均衡，乃提出輔助原則作為權力分配之準則。本文首先探討輔助原則之意義與歷史淵源，並比較其與聯邦主義精神相符合之處，進而追索輔助原則如何引進歐洲聯盟體系內，在行政與立法程序如何適用。最後並探討輔助原則是否適合由法院裁判。

The establishment of the European Union has pushed forward the depth and width of European integration. Increasing amounts of Member States’ sovereignty has been transferred to the European Community, and the Council of Ministers has adopted more proce-dures of qualified majority vote in its important decision-making processes. As a result, Member States and their citizens have become suspicious and have begun to fear the expansion of the power of the European Union. The principle of subsidiarity is concerned with distribution of power, in which tension between centralization and devolution of power has always been inherent. The principle was adopted within the European Community as a mechanism to mediate the division of power between the Community and Member States, and try to defuse political conflict. The aim of this paper is to examine the development of the principle within the European Union system. It probes the meaning and historical background of the principle, its relationship with federalism, and its practical application and influ-ence in the political system. The paper also assesses the justiciability of the principle within the European judicial system.