Postmodernism is criticized because it brings relativism, irrationalism and political nihilism. Many Japanese authors blame postmodernism for proclaiming the transcendence of modernity, since there remains collectivism and authoritarianism in Japanese society. But, in English speaking world, some authors point out that postmodernism has positive aspects.They judge that postmodernism involve a movement beyond oppressive binary categories. In fact, the meaning of postmodernism is ambivalent. In this paper, I search for the possibility of postmodernism in politics and social theory. For this purpose, I examine the postmodernism in architecture and the 'post-Marxism' that E. Laclau and C. Mouffe propose as a political turn of postmodernism. To find the possibility of postmodernism, it is important to reformu late postmodernism. That is to say, we need to think that postmodernism has the continuity and discontinuity of modernism, or that postomodernism is after-modern rather than anti-modern. If this reformulation is performed, the task of postmodernism become to go beyond objectivism and relativism.