In the rural communities in less-favored areas (mainly hilly and mountainous areas) in Japan, the number of settlements which cannot maintain the community functions by themselves has been increasing because of the progress of depopulation and aging, so the necessity for achieving mutual supplementation of the community function by the settlement reorganization has been increasing. This paper consists of the following three points. 1) General view of settlement reorganization policy in Japan. 2) Case study of the T district in Japan. 3) Possibility of the settlement reorganization by the policy measures which obligate community members to work together. Main results are as follows. 1) There are several settlement reorganization policy measures, but many are still the model project stage, and not yet spread, so it is necessary to wait and see how these measures will develop. 2) The number of the residents of small-scale aging settlements who do not hope for the reorganization, nor feel the necessity of reorganization shall not be few. This will make great difficulty in the settlement reorganization process. 3) A local area activity promotion conference which derives from a former administrative unit like a former village has many functions to the settlement reorganization. 4) In the rural communities in less-favored areas, the policy measures which obligate community members to work together have widely spread. These are expected to play the supplemental role for the settlement reorganization. It is necessary to discuss among residents the activation plan and the future vision of the community, as well as to discuss the settlement reorganization.