This paper examines the legal status of North Korea under the Non-Proliferation Treaty (NPT). Some argue that North Korea has already withdrawn from the NPT, but for others, it remains a party. This division among international lawyers stems from a fundamental legal issue concerning whether the exercise of the withdrawal clause stipulated in Article 10 of the NPT is only subject to the subjective judgment of withdrawal states. Traditionally, the right to withdraw from disarmament and arms control treaties has been considered a sovereign right, and therefore does not require any acceptance or approval from other treaty parties nor to be reviewed by any international institutions. If one maintains this conventional approach, even in the case of withdrawal from the NPT, which is now almost universally recognized as the cornerstone of the non-nuclear proliferation regime, there is no room to ask whether North Korea is still under the obligations of the NPT. In recent years, however, there have been growing concerns regarding the use of the right to withdraw. Furthermore, there are doubts that the right should not be considered to exclude scrutiny from other international subjects since North Korea declared to exercise her right to withdraw from the NPT in 1993 and 2003. The declaration has revealed that the NPT has a loophole in which a malevolent contracting state could abuse the rights of nonnuclear state protected under NPT to develop a nuclear weapon program. This paper argues that the right to withdraw from the NPT is not only subject to the intention of the withdrawal state but arguably to the judgment of other relevant institutions － in the case of the NPT, the United Nations Security Council.