Which Courts can Try former or serving Heads of State for commitment of Crimes under international law? First chapter analyze State practice of Belgium, Germany & French about Exercise of Universal Jurisdiction over Senior State Officials.Is Immunity creates an Obstacle, when National court exercise such jurisdiction?National courts must follow the Judgment of the International Court of Justice in the Arrest Warrant Case. Second chapter contains analysis of Charters, Statutes & Judgments of some Internationalized & International criminal courts, about persons who benefits by immunity, whether personal immunity or functional immunity. This Book balance immunity of Heads of State with end impunity of them, under conventional and customary international law.