Abstract
I considered an organization form of sustainable at play-park for the Gakikko-club who was active in a playground of Arimafuji Park. As a result, three points of the following became clear mainly. 1) Because they raised a vague slogan such as " Play in earnest " , many citizens with various thought were able to participate. 2) Because there is an end called the graduation to a student, the member changes every year. A result, always new way of thinking and activity are developed. 3) There is the member of society staff, the administration person, and park managers of Arimafuji Park as the system supporting the student.
