Cartel is one of many prohibited acts that regulated under Antimonopoly Law. It can harm the business activity by creating unfair business competition. Per se illegal is an approach used in most of the countries that have Antimonopoly Law in effort to resolve cartel in business competition. This paper discuses two matters: how per se illegal is used as an approach in Japan and Korea as one of the way to resolve cartel and how Indonesia used per se illegal as an approach to resolve cartel. In which, cartel is stipulated in article 3 of Antimonopoly Act in Japan, article 19 of Monopoly Regulation and Fair Trade Act in Japan and article 5 (1) of Law No. 5 of 1999 concerning the Prohibition of Monopoly Practices and Unfair Business Competition in Indonesia. Analysis is done by comparing facts within applicable laws and regulations in Japan, South Korea, and Indonesia concerning per se illegal. This legal research uses normative research such as statue approach which is the Antimonopoly Act, Monopoly Regulation and Fair Trade Act, and Law No. 5 of 1999 concerning The Prohibition of Monopoly and Practices and Unfair Business Competition and comparative approach in order to compare the regulation of per se illegal as way to resolve cartel between Japan, South Korea, and Indonesia. Per se illegal is used in all of the countries mention above as an approach to resolve cartel.