According to legal history and legal thoughts, the principal part of the science of present commercial law is to research the legislation and interpretation of law from the point of laying stress on the importance of the social function of business. I can show certain examples of this tendency. As to legislation, I point out the 1981 Ammendment of the Code of Commerce. The principal examples of this new legislation, from point of view above-mentioned, are the rights of shareholders to make proposals to general meeting of shareholders and the exclusion of so-called Sokai-ya . About the board of directors, the clear regulation of its authority prevents the arbitrary acts of president and officers of the corporation. As to the interpretation of corporation law, from point of view abovementioned, the doctrines of the protection of creditors and shareholders of subsidiary corporation are decided by several courts. One of them is substantially a copy of Deep Rock Doctrine in U.S.A. and other several decisions depend on the doctrine of“piercing the veil of corporate entity.” From point of view above-mentioned, as to ordinary acts of business, there are several doctrines about the validity and interpretation of general clauses of business contract (in German, Allgemeine Geschäftsbedingungen), such as the doctrine of contra proferentem and the doctrine of ejusdem generis. From the same point of view, as to the extraordinary acts of business, i.e. the responsibility of business for damages caused by it, the main tendency is from“responsabilité”to“garantie”(according to Prof. P. Durand), that is to widen the cause of responsibility and to limit the amount of responsibility. And further more, at present the responsibility of business is generally covered by insurance and re-insurance, and the damages are divided among many persons of the world. That is the best method of dissolving the problem of the business responsibility for damages caused by it. In short, the principal point of the science of present commercial law is to lay stress on deciding problems by the social function (useful) of business and many examples of present commercial law show the correctness of this point of view.