美國證人刑事豁免權制度係在限制不自證己罪之特權，而強制其為自我入罪及對共犯為不利之陳述，以瓦解組織性、國際性、科學性、隱密性及重大性等犯罪類型的案件，以維護發現真實之利益。簡言之，此制度係證人不自證己罪特權之利益與發現真實之公益的利益衝突下，因應而生的利益衡平制度，即不但可避免證人陷入自我入罪之風險，又可兼顧發現真實之公益。至於應如何將證人自我入罪之風險移除，即涉及到不自證己罪之理論基礎為何，本文認為應採「避免使人民陷入三難困境」。又證人刑事豁免權制度在美國法上之演進，起初係採「證言性豁免權」標準，嗣因受到對證人保護不足之質疑，而無法符合不自證己罪特權對證人之保護，而變更為「行為豁免權」之標準；惟行為豁免權之標準在美國法上亦受到質疑，即該標準所提供之保護範圍太過廣泛，對刑事訴追上發現真實之利益，會造成嚴重之妨礙，因而又變更為「衍生性使用豁免權」之標準，該標準迄今仍為美國證人刑事豁免權制度之主流標準。未來若美國證人刑事豁免權制度欲引進我國，將面臨較大之問題即是該制度在我國法下是否有違憲之疑慮，本文即以司法違憲審查標準加以檢驗，而認為該制度應能通過前開審查，是未來該制度如引進我國法，亦應屬合憲之法律規定，且具有正當性基礎而可合憲建構起此制度。

American's Witness Immunity is a limit to privilege against self-incrimination. It enforces witness to make statements against himself/herself or conspiracies so that organized, international, scientific,or serious crime can be defeated and the interest in truth-finding can be preserved. In summary, this Immunity is a balance between witness's privilege against self-incrimination and truth-finding. It prevents witness from incriminating himself/herself on the one hand and preserves truth on the other hand.The author suggests "preventing from trilemmas" as the rationale regarding privilege against self-incrimination
and it can avoid the risk of witness' self-incrimination. In the history of American's Witness Immunity, the standard of "Testimonial Immunity" was adopt at first, but the protection of witness was thought insufficient, so the standard changed to "Transactional Immunity." However, the standard of "Transactional Immunity" was criticized that the wild scope of protection would hinder the truth-finding process. Thus, the standard of "Use and Derivative Use Immunity" was adopted and keeps as a major standard to date. Should Witness Immunity being introduced to Taiwan, whether it conforms to Taiwan's Constitution would be doubtful.
This article researches American's Witness Immunity in respect
of judicial review of constitutionality and holds Witness Immunity conforms to Taiwan's Constitution.The system of Witness Immunity can be justified and set up constitutionally in Taiwan Law.