雖然境外取證等程序議題早因刑法中的管轄規定而存在，但近年來國際交流日益頻繁，越來越多的犯罪逾越一國的邊境，如何獲得境外證據、境外證據在何等條件下在本國的刑事審判程序中具有證據能力，而司法互助在其中可以扮演什麼角色等，業已成為刑事訴訟研究領域相當重要的課題。事實上，對於實務而言，不管立法者是否已建立完備的法制，也不管學者對問題已有認知，並提供有用的意見，實務工作者都必須處理送到眼前的跨境／境外刑事案件。本文即是以最高法院近十年來對於境外證人供述證據的判決為對象，探索其所累積而出的處理準則，並進行憲法、訴訟法與新興的跨境法學的分析，最後提供相關的處理建議。本文同意，但當犯罪跨過一國的邊境，無可避免地因為司法主權等因素，阻礙這類案件的處理，而給犯罪者可乘之機。但本文認為，全球化不僅提供犯罪者機會，也創造各國政府各類合作的架構。當人權的普世價值越來越受到肯認，境外／跨境刑事案件的被告不該淪落次等境地。即便是跨境／境外刑事案件，也必須注意犯罪打擊與人權保障之間的衡平。

The needs to conduct extraterritorial criminal investigations and to use extraterritorial testimony have long existed in the criminal justice system due to the complex jurisdiction rules in the criminal law. But such demands have been foregrounded with the rise of the globalization in the recent decade. The increasing numbers of extra-/trans-territorial crimes thus pushed the courts in Taiwan to create certain evidential rules to admit extraterritorial evidence. Studies show that the courts tend to favor the prosecution in these cases. The courts must have felt the pressures to handle extra-/trans-territorial crimes, so that they have created rules that the current criminal procedural law does not allow, and thus violated the constitutional rights of the defendants. While acknowledging the needs to combat extra-/trans-territorial crimes, this paper urges the courts to respect the constitutional rights of the defendants in every case. Miscarriages of justice could equally happen even in strong cases in the public eyes.