Japan has been suffered from frequent disasters related to erosion and sediment movement in mountains such as mountain collapses, debris flows and pyroclastic flows, because of both primary causes such as steep mountain and vulnerable geology and provoking causes such as torrential rains, earthquakes and volcanic eruptions. Now the mountain surrounding environment is changing rapidly and related complicatedly. Because of climate change, occurrence of localized torrential rain is increasing, and big scale local floods and droughts will be occurred. In addition, social changes, such as aging and decreasing population in mountain areas make it difficult to treat forest properly and it causes different types and scales of damage. Though local organizations such as fire volunteers have been developed for disaster risk reduction in mountain areas, newly introduced organization, so-called voluntary self-help organization has been promoted in Japan. The research field is focused on Reihoku area in Kochi, because the area is a typical mountain area with frequent mountain disasters, decreasing population and high rate of old population. In this research, issues of fire volunteer and voluntary self-help organization are analyzed and compared based on a literature review and questionnaire survey to suggest possible disaster risk reduction.