After the end of the Second World War, stable supply of energy, low-cost supply, and environmental protection have become three major goals for Japan’s energy policy. Nuclear energy has become the first choice for Japan due to its advantages in terms of its cost, secure supply, and greenhouse gas emissions. After the Fukushima nuclear disaster, the Japanese central government was obliged to review its nuclear energy policy. The “anti-nuclear” camp and the “pro-nuclear” camp have been engaged in a heated debate regarding the adjustment of energy structure and the prospect of nuclear energy policy. The former offers multiple reasons, such as the Fukushima disaster, frequent nuclear accidents, and nuclear waste disposal difficulties, as evidences against nuclear energy, while the latter maintains that from energy, economic and political perspectives there are realistic reasons for continuing the development of nuclear energy. In the post-Fukushima era, constraining factors on developing nuclear energy are growing, and the development of nuclear energy is full of uncertainties. The prospect of Japan’s nuclear energy policy hinges upon the degree of progress in elevating nuclear safety, updating nuclear safety culture, and strengthening the public’s acceptance.