The importance of cyber security has recently been highlighted in national security. Since 2004, ‘The UN Group of Governmental Experts in the Field of Information Security (UNGGE)’ has occurred four times. The consensus report 2013 adopted by the third UNGGE agreed that existing international law, particularly the Charter of United Nations, applies to the 'Use of ICTs by States', namely cyberspace. The fourth UNGGE adopted the report on how existing international law applies in cyberspace, as well as voluntary and non-binding norms for responsible behavior of states. The fifth UNGGE, which will begin in August 2016, is expected to significantly accelerate the development of international law and norms for cyber security issues. This session will discuss the UNGGE's past achievements and future directions on the application of international law and the development of voluntary norms for cyber security.