[en] The Niigata-ken Chuetsu-oki earthquake attacked the Kashiwazaki-Kariwa nuclear power plants on October 16, 2007. Although the earthquake caused stronger ground motion than assumed, the nuclear reactors in the operating mode were shut down with the most significant safety measures functioned and the nuclear power plant safety was maintained. However we should learn something important about the fact that much stronger ground motion than assumed attacked the nuclear power plants. This might bring about increased uneasiness for us to have the same thing that could happen in the near future in the case of 'Hamaoka nuclear power plants with a huge earthquake'. There are many reasons why the Hamaoka nuclear power plants are dangerous as follows: (1) the nuclear power plants would not be strong enough for the earthquake exceeding the design, (2) 'conservatism improvement' work is not based on scientific reasons, not enough in reality, (3) 'super huge Tokai earthquake' might attack those and (4) 'sufficient conservatism' might be made by misleading. (T. Tanaka)