In issues involving violations of antitrust law, such as the elimination of competitors, or in disputes concerning trade contracts and business alliances, etc., the amount of compensation for lost profits can be a major point of contention. However, much of the consideration given by the lawyers involved in such cases does not necessarily focus on the amount of compensation for damages, which can be outside the scope of legal theory. Indeed, it seems that generally, not enough has been done to date to ensure that practical measures are taken, contrary to the expectations of the parties to the deal. This seminar analyzed the Nipro Case the Usen Broadband Network Case and other related cases to explain the problems of claims in lawsuits; the ideal course of a claim; and the approach in economics.