This paper aims at finding out what caused the revival of mass demonstrations in Japan with the Fukushima nuclear disaster in 2011 as a momentum. This paper shows that it is the new media environment which acted as the main reason demonstrations in large scale revived in post-Fukushima Japan, a country where there had not been mass demonstrations since the 1960s and the 1970s when radical protests were more prominent. In the past, old media such as newspapers and broadcast impeded spread of protests, forming negative discourse against social movements and blocking information on any movement itself. Since around 2011 when the anti-nuclear protests occurred, however, the digital devices such as smartphone have diffused rapidly in Japanese society and the use of SNS(Social Networking Service) has expanded dramatically, connecting people and providing information across borders. This paper insists that the new media environment, new media replacing the roles of old media, has created discursive opportunities for social movements and mobilized tens of thousands of individuals without formal organizations. With digital media playing more important roles in spreading news and connecting people, and with many Japanese people coming out of the shells from the experience of mass anti-nuclear movement, now the Japanese do demonstrate. Japan has started forming a culture of protests.