In the second millennium, the UN, EU, and WHO have been encouraging social participation by the aged to foster “active ageing”; thus, Korea has been emphasizing the importance of social participation by the aged in its Seromazi Plan. However, Korea’s welfare policies for the aged concentrate mainly on income security and health, whereas discourse on the social participation of the aged is still in its infancy. This dissertation seeks to analyze the social participation of the aged and support policies for this in Japan in order to derive lessons on welfare policies for the aging society in Korea. The study showed, first, that social participation by the aged in Japan is closely linked with the local communities, occurring with mutual cooperation between the government and the people. Second, social participation of the aged differs according to such attributes as health, employment, wages, etc.; therefore, support policies must take these elements into account. Third, social participation programs create diverse personal and socioeconomic utility, but many problems remain. Finally, in Japan, consistent and proactive efforts to increase social participation by the aged were made within the framework of a social welfare policy referred to as the Japanese government’s measures for an aging society.