An international capital transaction is activated by the globalization of the capital market, and, not to mention national economy, there is the need of the argument over hostile mergers and acquisitions because there is a lot of influence to give the world economy. Such present conditions would cause the argument over the introduction of the poison pill as the defensive measure for the hostile buyout, too. Of course, for a defensive measure for the company buyout, various methods are developed including a method to make the aggregate market value of stocks through management to raise a corporate value. However, it is a fact to but consider the charm that poison pill has by all means. Even if various legal requirements are necessary for the appropriate use when they introduce poison pill, it is thought that the existence of the independent outside director performs a very important function. Of course there is not an outside director system despite almighty. However, except the position called the director, it is a fact that the existence that the judgment that is fair in change situation of the control is possible is the independent outside director who does not have an important interest for a company. With the existence of an effective capital market, the appropriate judicial decision of the court, and the display of the monitoring function by stockholders is important, but, for the prevention of abuse of the poison pill, the role of the independent outside director will be very important. There is originally a function and an ability of effective resource allocation in the capital market. By the way, the effective solution by the market function may be difficult. Particularly, in the case of hostile buyout, it may be necessary to intervene positively seeing from a Great Society-like standpoint even if it is not illegal. A thing for a menace of the hostile buyout by the logic of the finance is takeover defense means such as the poison pill. There is the opinion against the introduction of the defensive measure including poison pill, but it will be necessary to pay attention to resistance to protect invisible value such as corporate culture or area culture not to be able to express with the simple numerical value. Because it might hurt even national economy not to mention the mission of the company above all when a system concerned is in an unripe state, I think that company buyout-related system maintenance is essential.