In the aftermath of the attacks of Sept. 11, the threat of terrorism was internationally recognized and the human resource capacity building has been underway as an urgent task. Despite the measures each country has since placed including stricter regulations, nuclear/radioactive materials related thefts and sabotage are still being observed; the threat of nuclear terrorism in international societies is only increasing. In order to respond to these still emerging threats, the reinforcement and sustenance of nuclear security system is necessary. With examples and comparison to nuclear safety, this article examines the importance as well as issues the basis of such system ? human resource capacity building in the field of nuclear security and the fostering of its culture ? face.