The role of Empirical study in legal decision, even in the rule making, was increased by the economic development with the occurrence of economic realism. The incensement of economic implication of the law, without exception, impacted to the court’s ruling in the antitrust case and the antitrust law-making itself. Now it is one of the common way, court use concepts and theories developed by economists and weaves economic concepts into decisions to support their result. The classical perspective of economic theories regarding antitrust law was start from early theorist Adam Smith in 1776, even it denied the economic implication. Through this dissertation, it was examined several modern economic theories along with Posner’s economic implicati...