The purpose of this study was to examine why the reminiscence intervention was effective. The group reminiscence intervention was performed 13 sessions for eight elderly people living in the community. Using the PGC morale scale and Tree test as indices, these were performed one week before the start of the reminiscence intervention (before the intervention), the sixth session (during the intervention), the thirteenth session (after the intervention), and one month after completion (one month after the intervention).On the PGC morale scale, the subscale "loneliness / dissatisfaction" scores tended to be lower after the intervention than before the intervention, and lower after the intervention than during the intervention. There were no other significant differences.In Tree test, focusing on the changes in the impressions of the participants four times, it was considered that the changes in Tree were classified into three types. That is, "The tree stood on its own during the reminiscence intervention, but needs support after the intervention or one month after the intervention", "From before the intervention to one month after the intervention, there was almost no major change or the form changes after the intervention, and one month after the intervention, the tree became slightly rich" and "Trees changed from one to two during the intervention".According to the analysis based on the narrative, the following was considered: this interactions of <talking about oneself> and <listening to the experiences and thoughts of others> in <a special place that is different from everyday life in reminiscence group>, led to < reflect on one's experience> and < others listen to their stories with interest>, and was a necessary element for a rich reflection.Also, in such a safe place, <Expression and sharing of emotions> by each other was not only fulfilled mentally, but also led to <objects and events of conflict could be meaningful from a different perspective than before> and <being able to perceive oneself positively in the past and present>, and <respect for oneself and others and share the creed in the future>, leading to the choice and will of the way of life in the future. This was thought to be the effect of the reminiscence intervention.
