The concept of ‘Transitional Justice’ is used in relation to how to deal with crimes against humanity or state crimes against humanity rights committed in war or dictatorship after the end of the war or dictatorship. The key tasks of ‘Transitional Justice’ are the achievement of reconciliation・social integration and the pursuit of justice. To achieve these key tasks, the ‘Justice Model’ and the ‘Truth-Reconciliation Model’ can be chosen. The Justice Model focuses on the criminal responsibility of the perpetrator. In this model, the criminal court is the central body and judges serious human rights violations such as genocide, crimes against humanity and state crimes against human rights. The Truth-Reconciliation Model, on the other hand, seeks reconciliation by discovering the truth of serious human rights violations through official government investigations. In this model, the Truth and Reconciliation Commission(TRC) is the central body. At this time, the Truth and Reconciliation Commission pursues the cleansing of individuals, community- building, and consolidation of political change. In this paper, first, it was examined whether there is a need for amnesty, immunity, or mitigation according to the Truth-Reconciliation Model when the perpetrators of state crimes against human rights actively cooperated in the investigation process(Ⅱ). In addition, as a comparative law research method, cases in foreign countries in which amnesty, immunity, or mitigation were implemented or not implemented were reviewed(Ⅲ). And the contents and problems of the reconciliation provisions of Fact-Finding Act on Suspicious Deaths in the Military, the Past History Reorganization Act, and the 5・18 Fact-Finding Act, which were introduced in domestic law, were examined(Ⅳ). Based on these discussions, in the future, when introducing a reconciliation regulation that recognizes amnesty, immunity, or mitigation to cooperators in investigations of state crimes against human rights in Korea, what form and content should be included and specific introduction methods were suggested(Ⅴ).