Japan has been characterized as a "peace-state" after the end of the Second World War. Under the so-called peace constitution, diverse military-related norms such as "exclusive defense doctrine", "three principles on the ban of military weapons export", "three Non-Nuclear principles", "principle of peaceful use of space", "principle on the ban of offensive weapons" and so on have been functioned as important tools to prop up the peace state. Due to these multiple anti-military norms, many experts on Japanese security policy have considered Japanese society as one of exemplary anti-militarist society. However, we are witnessing the revision or abolishment of these diverse anti-military norms in recent Japan. In 2008, Japanese government decided to discard the long-standing norms of peaceful use of space and enacted the Basic Law of Space in which enables the development of space assets for the purpose of national security. In addition, Japan also abolished the concept of basic defense force which implies the minimal military capability in the National Defense Program Guideline which was released in 2010. Replacing it, Japan put forward the new concept of dynamic defense force which means that Japan can equip herself with high-level military capabilities. Furthermore, Japan loosened its strict principle on the ban of military weapons export in the late 2011. As a result, Japan can export its military weapons to other countries and propel a co-development of high-level military technology with the collaboration with other western countries including the U.S, its long time ally. Considering these changes in terms of Japanese military-related norms, we can say that Japan is gradually changing its security policies into a more realistic one.