It has been said that the spread of social networking services (SNSs) has changed the style of social movements. One of these changes has involved gathering participants, and has been called “the revolution of mobilization.” However, the membership of many Japanese environmental movements are aging and decreasing in number. They are faced with a labor shortage, so how far is “the revolution of mobilization” progressing? This study examines how environmental citizen groups in Japan are using information and communications technology (ICT) to expand their membership and how ICT is changing citizen movements. We interviewed six nationwide environmental citizen groups, three local environmental citizen groups, three nationwide intermediate support organizations, and three local intermediate support organizations. Since these environmental citizen groups possess minimum manpower required to sustain their activities, though they are prepared to use ICT, they are unable to organize, strengthen, or expand. Although the aging membership and shortage of staff are recognized as a big problem, they are unable to solve these problems fully. Although new movements are born from younger generations and big cities, the existing groups have not sufficiently engaged with ICT to develop their movement. In the present situation, existing groups cannot avoid the reduction and aging of their membership, and their activities may decline. Filling the generational gap and regional gap in citizen movements therefore remains a problem.本研究の遂行にあたっては科研費助成金（基盤研究C：25350440：ボランティア参加の機構解明とそれを活用したボランティア獲得の為の情報システム開発：代表前田恭伸）を受けている
