Upon Japan’s ratification of the Convention on the Elimination of all forms of Discrimination against Women in 1985, certain law reforms for gender equality were realized. However, international human rights law has impacted limitedly on the Japanese judiciary. The Women’s Convention has been invoked by parties in a number of cases, but so far has never been positively quoted by the courts. On the other hand, the jurisprudence of individual complaints under the Optional Protocol of the Women’s Convention has developed significantly. This paper introduces the case law of the individual complaint procedure of the Women’s Convention, and identifies its significance in comparison with Japanese jurisprudence. As the jurisprudence of individual complaints under the Women’s Convention is still in the law-making stage, the author encourages the Japanese government to ratify the Optional Protocol so that it can participate in the process of developing this jurisprudence.