Purpose - This paper aims to obtain a theoretical understanding for the relationship among the elderly's leisure activity, social support, life satisfaction and mental loneliness in their life. This paper has the purpose to draw policy implications by the course of research and study as well as to find alternatives in enhancing the elderly’s psychological well-being in a practical dimension. Research design, data, and methodology - Data has been collected from 380 elderly persons participating in leisure activities in 10 senior welfare service centers located in the Seoul area. A structured questionnaire sheet was used, and as the main analysis method for hypothesis verification, the hierarchical regression method was used. Results - Social support is moderating factor for the relationships among the productive leisure activity, life satisfaction and mental loneliness, but does not play the moderating role in the relationships such as consumptive leisure activity, life satisfaction and mental loneliness. Conclusions - It is necessary to make efforts to provide policies for promoting and expanding the elderly's participation especially in productive leisure activity. And also, an institutional support should be provided for maintaining and expanding a stable social relationship network for the elderly’s participation.