This article attempts to examine the basic theory of statutory interpretation in the United States, recognizing that is becoming an important theme of administrative law in education and trial practice in recent Japanese law. In the 18th century in the United Kingdom, textualism was adopted as a rule of legal interpretation. In the United States during its founding period, the anti-federalist (Jefferson) and federalist (Hamilton) factions disagreed about the appropriate practice to follow. However, in the 1850s, textualism was adopted in both trial (Marshall Court) and administrative practices (Attorney General). The late 19th and early 20th centuries marked the emergence of a new statutory interpretation theory with legislative materials. This new theory was intentionalism. It was clearly established by the legal realism theory in the 1930s and 1940s, and by the combined factors of legislative activity and the litigation practice of administrative agencies during WWII from the New Deal period. However, because of concerns regarding the transformation of the administrative state, from the 1950s, legal realism became wary of intentionalism. The theory of legal process (Hart & Sacks) led the way to the new statutory interpretation theory. Purposivism saw legislative history as showing legislative intent in an abstract manner. Since the 1990s, the Supreme Court has adopted the methodology of new textualism. New textualism claims the complete elimination of the use of legislative history. There is also the question whether the value of democratic legitimacy or the rule of law can be implemented far enough. This article seeks to answer this question and asks how to envision statutory interpretation theory using legislative documents.