In Japan, an increase of elderly people living alone has become a serious problem with the progress of aging. After 2013, the number of lonely death of elderly people living alone is increasing rapidly. Since lonely death tends to increase in the future, it is one of the problems to be solved by the government agencies and the families. The tracking system of elderly has been researched and developed by a number of companies and universities. However, many of those systems have required an operation of the elderly his/herself, or have become a large-scale system configuration. In this study, we propose an elderly monitoring system which is able to detect the abnormal state without stress of elderly. The proposed system consists of single monitoring device and several sensor nodes, and provides elderly state information to the family and/or government agencies, at the specified time and at the time that abnormal state is detected.