Historically, Local Currency Systems (LCS) were founded in 1930s when economic depression spread widely around the world to support the local economy. However, currently, LCS are seen as a tool to strengthen solidarity in the local community by solving social welfare issues and environmental issues uncovered by the state. This study aims to clarify the social functions for participants in LCS through a case study of Local Exchange Trading Systems (LETS) in Sweden. The focus will be on the role of personal relationship networks. This study examines an in-depth interview with the organizers of seven LETS associations in three cities in Sweden (Stockholm, Göteborg, and Lund) to reveal their purpose. A questionnaire survey was done in BYTS, the oldest and largest LETS to date in Sweden, to test the realization of the previous revealed purposes. Additionally, we use the methods of Social Network analysis to grasp the characteristics of personal relationship networks in LCS. The study can show that one of the main aims of these LETS—to develop social networks—is indeed accomplished. Not only was the social functions of the LETS a motivation for the effective participants to join BYTS, but they also could establish personal relationships. The opportunity to make friends was especially attractive for low-income, low-educated and retired persons. Furthermore, we identify four characteristics of LCS networks ; such as expanding peer to peer networks without mediation of the office (a network center) and creating the system for evaluation of goods and services which are hard to evaluate in the national currency system of our dehumanized society. The result suggests that LCS can contribute to visualize various potential needs embedded in the participants' mundane lives which usually are ignored by the public policy and the market through promoting peer to peer reciprocal exchanges, and therefore we can conclude that personal relationship networks created by using LCS has the important function to revitalize local community.