Is the current regional security environment suitable for Japan’s remilitarization? This paper attempts to analyze the recent security condition in East Asia to see whether the structural requirements for Japan’s remilitarization are already in place. It first looks into the existing literatures examining the issues of Japan’s remilitarization. It then adopts the hegemonic stability theory as a basis for the theoretical structure while presenting its limits to draw a more suitable framework for the current security condition in East Asia. After that, three cases of China, Russia, and North Korea in recent years are examined to see whether the security condition in East Asia fits the condition of crisis described by the theoretical argument. It is revealed that they represent long-term, immediate, and mid-term threats, respectively. Furthermore, while each of these actors did not fulfill all necessary standards to become a single challenging state, taken together, their actions have created the perception of regional hegemonic challenge in the eyes of the US and its key allies. In conclusion, this research argues that the structural requirements for Japan’s remilitarization are now present.