This chapter begins with a brief historical view of the development of Japan's nuclear policy. It examines arguments for its position on the use of nuclear technology, including those in favour of a nuclear weapon option, the difficult issue of a nuclear co-operation agreement with India, and prospects for Japan's nuclear policy in the future. Japan's nuclear policy has shown ambivalence between pacifism and pragmatism. Japan's nuclear policy comprises two aspects. The first is promotion of peaceful uses of nuclear technology such as nuclear power production. The second is the total negation of nuclear weapons, which is articulated as the so-called Three Non-Nuclear Principles: non-possession, non-production and non-introduction of nuclear weapons. The Japanese Government must take into consideration Japanese anti-nuclear feeling as well as the potential economic benefits of such co-operation with India, a country that never accepted either the Nuclear Non-Proliferation Treaty or the Comprehensive Test Ban Treaty.