I will clarify the figure of the Japanese living constitution. The theory of living constitution in Japan has focused on constitutional change by political branches without formal amendment of Constitution. On the other hand, there have been a few discussions over living constitution by the judiciary. In spite of a few arguments, the Japanese Supreme Court has sometimes determined constitutionality of laws in the light of social change. In fact, the Court has implemented living constitution through responding to social change. However, it is a little different general living constitution because the Court doesn’t change constitutional interpretation. Although the Court adjusts laws to social change in the constitutional case, it doesn’t change constitutional meaning. The Court just held that the law was invalid as it was unreasonable in current situation even if it had been reasonable before. It seems that this is living constitution formed in Japan.