Social capital increases commitment to the networked relationships and the ability to mobilize people to collective action (Larsen et al., 2004; Ellison et al., 2007). Social media may be utilized to attract a large number of people, encompassing those who are uninterested in social problems; people who have low commitment can join traditional social movements. In these aspects, a weak but broadly tied network constructed by social media has complementary features. This study considers the role of bridging social capital in social movements as the benefit gained from social media of a broadly connected network.