This study focused on family group in Japan, a family encounter group during the child-rearing period, which provides daily support for the children who participate in the group over years. The purpose of this study was to gain insight into ①the characteristics of the participants, ②the characteristics of the daily support, and ③the content of underlying experiences and the intrinsic mechanisms of the group, which would contribute to understanding of this group from a viewpoint of clinical psychology. ①Parents may have had some contact with the encounter group before they started parenting. ②This group is positioned in the children’s daily life as a world where they are deeply accepted, which functions as daily support for them. ③The content of underlying experiences and the intrinsic mechanisms of the group including: setting of an environment that creates extraordinary experiences and the intervention of staff between parents and children; the liberating experiences and challenges of children in the natural environment and the presence of staff who act with them and lead various customs; the internalization of an attitude of respect for others and the experience of the value of meeting others, which are characteristic experiences of person-centered encounter groups; and factors that allow it, such as reunification with long-term participants, the free time frame, facilities, and the verbal communication intrinsic to various customs that are formed in the group.