The first purpose of this paper is to identify factors having an effect on the user satisfaction of the SNS(Social Network Services) users and to examine causal relationships among those factors. The second is to examine how the causal relationships between the factors could be changed in the service types in SNS, which would be divided into web based SNS and mobile SNS. For achieving the purposes, we established the research model and hypotheses based on Information Success and Technology Acceptance Model. The characteristics of the SNS users consist of Individual Innovation and Social Influence while the characteristics of the SNS system consist of Information Quality and System Quality. The hypotheses were verified by analyzing data, which was collected from survey research on users of the SNS, with AMOS 18.0 statistical package. As a result, the first, we observed that more important the SNS users would consider the social relation, more useful they would recognize the function of SNS. The second, we observed that faster and easier the users could obtain hourly information in diversity, more useful they would recognize the function of SNS. The third, we observed that more innovative the mobile SNS users would become, more negative they would consider the usefulness of SNS. The fourth, we observed that more important the web based SNS users would consider the social relation, more negative they would consider the usefulness of SNS.