本論文以近年歐盟會員國境內之孤狼恐怖攻擊趨勢出發，分析歐盟因應孤狼恐怖主義威脅所制定之反恐政策，同時評估歐盟反恐政策之內外反恐成效，藉此檢視孤狼恐怖主義與歐盟反恐政策之因果關係。孤狼恐怖主義緣起於美國「無領袖反抗運動」與「暴力激進化」，並透過「全球伊斯蘭反抗運動」與「外國恐怖主義戰士」成為歐盟內部安全之威脅來源；而歐盟反恐政策之決策機構與執行機關，業已透過戰略方針與行動計畫等歐盟反恐法律文件，對內建立合作機制與輔助工具等內部反恐網絡，藉此強化歐盟與歐盟會員國之間的警察合作、司法合作、資訊與情報交換合作、以及邊境安全合作；對外則透過國際協定形式，與重要第三國以及國際組織建構外部反恐網絡，以雙邊與多邊反恐合作形式強化歐盟反恐能量。本論文亦以四起孤狼恐怖攻擊個案分析歐盟會員國層級之反恐措施，分析近年歐盟孤狼恐怖主義之現況與趨勢。 本論文發現，歐盟孤狼恐怖主義來自「聖戰恐怖主義」、「本土恐怖主義」、與「外國恐怖主義戰士」等三種威脅，而歐盟近年因應孤狼恐怖主義威脅之反恐政策與措施，已朝向2005年11月30日歐盟部長理事會《歐盟反恐政策》四大反恐戰略的「預防」層面發展，並以外國恐怖主義戰士為重要反恐目標；此外，歐盟除了著手打擊「激進化」與「暴力極端主義」等導致孤狼恐怖主義之根本原因原因外，亦持續因應敘利亞與伊拉克等衝突地區之「返國外國恐怖主義戰士」所帶來的後伊斯蘭國時代孤狼恐怖主義威脅。 / With the trend of lone-wolf terrorism in member states of the European Union, the thesis analyzes EU’s policy to counter threat from lone-wolf terrorism and also evaluates internal and external effectiveness of EU’s counter-terrorism policy, in an attempt to examine the correlation between lone-wolf terrorism and EU’s counter-terrorism policy. Lone-wolf terrorism originated in the United States from the “Leaderless Resistance” and “Violent Extremism” and further threatened EU’s internal security via “Global Islamic Resistance Movement” and “Foreign Terrorist Fighters.” The decision-making as well as the executing agencies of EU’s counter-terrorism policy has established mechanisms of cooperation and policy toolkits for internal counter-terrorism network by means of EU’s legal documents of counter-terrorism, strategic guidelines and implementing programs included, in order to consolidate cooperation of police, justice, exchange of communication and intelligence, as well as border security between EU and member states. Meanwhile, EU has also been constructing its external counter-terrorism network with bilateral and multilateral agreements with third states and international organizations of importance. The thesis also offers four case studies of lone-wolf terrorist attacks of EU’s member states to analyze conditions and trends of lone-wolf terrorism in EU. The thesis concludes that “Jihadist terrorism,” “Home-grown Terrorism,” and “Foreign Terrorist Fighters” are the three main types of threat of lone-wolf terrorism in EU, and that EU counter-terrorism policy has been developing strategy of “prevention”, one of which stated in “EU’s Counter-terrorism Strategies” of November 30th, 2005, by Council of the European Union, and considering foreign terrorist fighters as its main target. Additionally, EU has been countering not only root causes of lone-wolf terrorism, such as “radicalisation” and “violent extremism,” but also future threats from “Returning Foreign Terrorists Fighters” heading back home from Syria and Iraq in the Era of Post-Islamic State.