作為20世紀古典自由主義的代表性人物，海耶克（F.A. Hayek, 1899-1992）既是重要的經濟學家、政治思想家、社會哲學家與公共知識分子，同時也是不容忽視的法哲學家。在其經濟、政治、社會及法律思想中，「自由」（liberty）概念無疑居於關鍵地位，「法治」（the rule of law）更被他視為自由的基礎。此一「法治為自由之基礎」的法治思想，往往被歸為形式法治理論，因為海耶克主張法治不可包含追求實質資源分配的社會正義理念，只能以普遍性、抽象性、法律之前的平等、確定性等形式要件作為法治要素，以避免因專斷意志導致人治與極權狀況再度復甦，嚴重侵害個人自由。本文第二節探討海耶克法治思想的核心理念與論述理路，耙梳他如何從「自發性秩序」（spontaneous order）與「計畫性秩序」（designed order）、「自由之法」（the law of liberty）與「立法之法」（the law of legislation）的區分，論證自由、秩序、法律三者間的緊密關係，進而發展出「法治為自由之基礎」的法治理論。第三節針對海耶克的消極自由觀與法律平等觀進行反思檢討，本文認為，海耶克提出「自由即沒有強制」的消極性概念，最終傾向新羅馬理論的消極自由觀，也就是把自由理解為「沒有依賴」的消極性概念。此外，本文也指出，其法律平等觀蘊含的「形式適用」與「形式內容」兩項要素，並非不具實質評價立場的形式平等觀，而是在適用上偏向多數者價值觀、在內容上持進化論文化觀的實質價值論述。最後則從海耶克思想蘊含的兩大前提，總結本文論點。

As a representative of twentieth century classical liberalism, Friedrich August von Hayek is not only an important economist, political thinker, social philosopher and public intellectual, but a legal philosopher not to be dismissed. In his thoughts, the concept of liberty plays a central role and the ideal of the rule of law is regarded as the foundation of liberty. For Hayek, the rule of law means that government in all its actions is bound by rules fixed and announced beforehand. Accordingly, the rule of law is a formal conception in the sense that it precludes the idea of social justice pursuing the substantive distribution of resources. The formal conception of the rule of law only consists of three attributes: the general and abstract rules, rules being known and certain, and equality before the law. Without the rule of law, he argues, individual liberties are so apt to be coerced by the arbitrary will in which human society will finally step into the road to serfdom. Part II surveys the core ideas and main arguments in Hayek's formal conception of the rule of law. I will discuss two important distinctions in his legal theory: the distinction of spontaneous order and designed order and the distinction of the law of liberty and the law of legislation. Based on these two distinctions, Hayek develops his rule of law theory - the rule of law as the foundation of liberty - by arguing that liberty, order, and law are closely related. Part III criticizes his negative conception of liberty and his account of legal equality. This essay attempts to argue that his negative conception of 'liberty as the absence of coercion' is inclined to the neo-Roman conception proposed by Quentin Skinner arguing that liberty is better to be understood as the negative conception of no-dependence. Furthermore, I also argue that the two formal elements implied in his account of legal equality - formality of application and formality of content - cannot be sustained. They are premised on his preference to the substantive value of the majority and his evolutionary version of western legal culture. In conclusion, I will summarize the two theses implicit in Hayek's liberal legal thoughts.