This paper provides an overview of the studies of John Locke's works in post-war Japan. Among his works, the Second Treatise of Government attracted much interest because of its social contract theory. Anticipating the development of democracy in Japan, post-war studies of the Second Treatise often disputed whether Locke's political theory provided an applicable model and raised the issue of whether Locke's theory of "trust" should be examined in relation to his understanding of the English legal tradition.