In the disaster caused by the torrential rains in Amami Oshima in the 20th October 2010, mutual help among the neighboring elderly people resulted to minimize the damage. This mutual help seems to have been developed through the routines of everyday life as well as the time of disaster. In Amami Oshima of Kagoshima Prefecture where this research was conducted, the population aging rate is very high as reaching to 30.6% in 2012. Thus, in a regional society where aging rate is very high, natural disaster-prevention measures which give extra consideration to the elderly would be needed, since in such a society, the possibility for the elderly and the handicapped to fall victim to disasters is very high. The article describe in detail about rapid reaction, communication and real situation of the affected areas at the time of disaster based on my field research data in Amami Oshima, which often suffer natural disasters and the aging rate is very high. Then, after discussing major problems from the viewpoint of disaster prevention, issues for future measures and the ways of supporting will also be examined.