This study explored support method for victims of the Great East Japan Earthquake of 2011 based on experience of support activity for improvement of housing environment in temporary houses and examined reasons which realized the activity despite of limited resources. 1) Relationships of "support for supporters" was created based on sharing aid information among various support actors in the process of exploring correspondence to problems which cannot be solved by each actors. 2) "Trust" for others (supporters/other residents) are fostered and utilized in the process of decision-making under the uncertain situation.