我國「移民法」之規範方式具有刑事與行政法規範同在，處罰與職權規範兼備，行為規範要件與罰則併列，甚且授權驅逐出國之強制執行規定，甚至不配合執法要求，尚有罰鍰作為後盾。有關移民執法人員之干預性職權規定，進行行政調查蒐集違規資料，以作為處分或處置之基礎。再者，移民執法係為達其法定任務，規劃各項業務，而由勤務執法人員依法執行，常需施予相關職權措施來達成，職權措施多藉由勤務執行之「物理力作為」來加以完成，多起自「查證身分」，必要時亦將「暫時留置」相對人來完成蒐集執法所需之資料。又移民執法人員在執法係經由「判斷」與「裁量」，且需有「違法要件」與「職權要件」之合致，始得加以進行取締調查，若第一線執法人員進行違法嫌疑之「取締調查」，而認有違法要件之合致時，則再進一步移送由裁處機關或單位進行「裁處調查」。按法治國家之移民執法採行干預人民自由或權利之措施，應符合「法律保留」、「明確性」及「比例原則」。本文乃先對我國與日、美二國移民執法之「查察」職權加以引介概述，並進一步針對我國移民執法行使「暫時留置」與「查證身分」職權之法理與問題加以研析及檢討，並提出相關建議與結論，以供未來法制規範與實務改進之參考。

The “Immigration Act” has both criminal and administrative law regulation. Both punishment and power are regulated inside, and both the conduct requirement and penalty are juxtaposed; even the enforcement regulations such as deportation are authorized. Furthermore, there are fines when there is no cooperation with law enforcement requirements. As a basis for punishment or disposition, immigration law enforcement officers conduct administrative investigations as interventional power to collect information on violations. Furthermore, in order to attain its statutory tasks, immigration law enforcement power plans various tasks, and hand them over to immigration law enforcement officers. It often requires relevant power measures to achieve its purpose, and power measures are mostly accomplished through “physical force”, which is mostly by “identity checking”. When it is necessary, the counterpart will be “temporarily detained” to complete the information collection to meet the needs of law enforcement. In addition, immigration law enforcement officers conduct investigations based on “judgement” and “measurement”, while “illegal conditions” and “power condition” are consistent. If the first-line law enforcement officers conduct “illegal suspect investigation” and deem that there are illegal conditions, then the officer will further send the case to tribunals or units to conduct “tribunal investigation”. When the immigration law enforcement of a nation under the rule of law adopts measures that interfere with the freedom or human rights, it should comply with “statutory reservation”, “intelligible principle” and “principle of proportionality “This article first introduces and summarizes the “inspection” powers of immigration law enforcement in my country, Japan, and the United States, and further studies and reviews the legal principles and problems of my country's immigration law enforcement in exercising the powers of “temporary detention” and “identity checking”; and puts forward relevant suggestions and conclusions, for references to future legal norms and practice improvement.