Through revision of its constitution, North Korea declared itself as a nation that have had nuclear weapons. Even though North Korea made an announcement not to proliferate nuclear weapons and stop doing nuclear research, it ignored demand from international community. Why did North Korea declare itself as a nation that have had nuclear weapons despite continuing criticism from international community? Unless Kim Jong-un administration don't officially attach the content declaring North Korea as a nation that have had nuclear weapons in its constitution, its administration can't be able to control mind of its people. However, this remark from North Korea only makes sanctions from UN more intense. In the situation which international communities including United States made a announcement it can't recognize the statement North Korean government published, We'd like to send a message to Kim Jong-un that if he regard nuclear test and missile launch as a return for negotiation with international community, that is definitely his mistake.