Confessions of a Mask (1949) and Forbidden Colors (1951-53) are important works for understanding the reception and development of Western sexology in Mishima Yukio. From the end of the Meiji period and into the Taisho period, a number of monographs on sexology were translated into Japanese. Japanese scholars and writers actively responded to this and published their own research. Mishima showed a great interest in such books and explored them with enthusiasm. He then wrote Confessions of a Mask and Forbidden Colors, which are both concerned with male homosexuality. It is noteworthy that Magnus Hirschfeld is quoted in Confessions of a Mask and Havelock Ellis's theory is mentioned in Forbidden Colors, though little discussion on this has been done in previous studies.

　This paper will complement previous research by empirically comparing Mishima's text with the books on sexology he used when he was writing Confessions of a Mask and Forbidden Colors. In order to do this, Mishima's collection catalogue and materials Mishima actually read are analyzed, and the difference between the original books and quotes are identified. In addition, by clarifying what knowledge of sexology is included in Confessions of a Mask and Forbidden Colors, on homosexuality in particular, and by examining the two works comprehensively, this paper presents the development and change in Mishima's homosexual discourse.