This paper examines aspects of the debate in American law regarding the method of statutory interpretation by administrative agency. It is not just the courts that interpret administrative law. In many cases, the first interpreter of administrative law is the administrative agency. Therefore, administrative interpretation precedes judicial interpretation. Of course, judicial interpretations are not legally bound by administrative interpretations, but it is undeniable that an administrative interpretation has a de facto effect on the subsequent judicial interpretation. In addition, since administrative interpretations are not subject to judicial review unless they become dispute cases, administrative interpretations continue to have a substantial influence until their illegality is confirmed. Until now, administrative law in Japan has been widely debated based on such administrative interpretations, but there has been no interest as to how administrative interpretations should be formed in the first place. It seems that there is an implicit rule that the method of statutory interpretation by administrative agency is similar to that of judicial interpretation. However, is this really true?
This paper considers American law as a comparative object. In the United States, statutory interpretation methodologies have been favorably discussed since the past 30 years. In recent years, some of the focus has been shifted toward administrative interpretation methodologies, mainly by the public law scholars. In the United States, which adopts the presidential system, the will of the parliament and the government do not always match as they are likely to have different democratic bases, and the party politics in voting is also not severe. Therefore, the question of how faithful the interpretation of the administrative body under the President's control should be to Parliament and whether the President and the current constitution of Parliament after the passage of the statute can be considered legally and politically are recognized as major issues. Furthermore, the dynamic theory clearly asserts that the method of administrative interpretation is different from that of judicial interpretation. Even under the parliamentary cabinet system, the composition of parliament changes with the change of government. The perspective of who is the legislator when interpreting the statute by an administrative agency will be essential in Japanese law.