軍隊社會中講求服從的紀律建構了「上命下從」的關係，上級長官會以軍事命令下達各種要求，以順遂軍事任務，特別是在作戰時，服從命令尤為重要。然而，在下屬執行上級違法的命令時，他是否該負刑事責任？這個議題在國際法學者間討論了許久，實踐上，戰後受審的被告時常以「上級命令」作為抗辯，即使第二次世界大戰後確立了上級命令不免除責任原則，國際間相關判決還是有不同的見解。本文以國際法之規範檢視美萊村事件三個案例，歸納軍人服從違法命令不免責之原則與例外之免責標準。

The discipline required by the military constitutes an hierarchical relationship. By this, it is meant that orders and commands from the top to ensure military operations are executed smoothly and successfully, and this is of crucial important especially during war time. Nevertheless, when executing an illegal superior order should the subordinate take for responsibility? The issue of accountability has been long discussed by international law scholars, and in practice many accused claim themselves to be following superior orders. Even though the main view holds that a defendant act pursuant to superior orders shall not constitute a defense per se after World War Ⅱ, there are still verdicts upheld otherwise. This article discusses the subject of 'defense of superior orders' with special emphasis on My Lai cases.