This study examined the antecedents of the formation of social capital on SNS. The authors divided a dimension of social capital into bridging and bonding social capital, and suggested that structural and relational characteristics of network would influence the formation of social capital. In addition, the authors suggested the formation of social capital would result in customer satisfaction and continuance intention to use SNS. Specifically, the authors suggested hypothesis as follows. H1: Network density will influence the formation of bridging social capital. H2: Network density will influence the formation of bonding social capital. H3: Network centrality will influence the formation of bridging social capital. H4: Network centrality will influence the formation of bonding social capital. H5: Trust towards SNS will influence the formation of bridging social capital. H6: Trust towards SNS will influence the formation of bonding social capital. H7: The formation of bridging social capital will influence satisfaction towards SNS. H8: The formation of bonding social capital will influence satisfaction towards SNS. H9: Satisfaction towards SNS will influence continuance intention to use SNS. The authors surveyed SNS users and conducted structural equation model analysis based on the result from the survey. The results revealed that network density and centrality influenced the formation of bridging social capital; while network density and trust influenced the formation of bonding social capital. In addition, the result verified that bridging social capital had an association with satisfaction and continuance intention to use SNS; while bonding social capital had an association with satisfaction, not with continuance intention to use SNS. This result expanded the scope of SNS and social capital literature academically by verifying the antecedents of the formation of social capital on SNS. Also, practical implications for SNS practitioners were followed.