This article is an attempt to develop the idea of peace education for adults through the assumption that, compared to peace education for children, educational approaches for adults are as yet undeveloped. This article also assumes that the progress of educational approaches for adults is necessary to the further development of peace education for children, as well as to the expansion of the theory. In navigating the argument around issues of peace education for adults, the article uses the example of educational issues faced by Amerasians in Okinawa. The article argues that language education is a fundamental aspect of peace education for adults. It also demonstrates that the content of language education for adults is different from the content of language education for children. Furthermore, the article defends peace education for adults, through language education, as the very first step towards creating peaceful conditions for the education of Amerasians in Okinawa.