Here we investigated the characteristics of users of an emergency system that tracks elderly people, known as the "elderly monitoring key ring." The relevance of a spreading policy or strategy and the user characteristics were investigated to develop programs conducted by local governments to manage unidentified elderly people with dementia. A questionnaire was conducted in July 2013 in a district of the Ota Ward in Tokyo. The questionnaire was administered to residents >65 years of age (N=7,608), of which 5,166 (67.9%) responded. Fully completed responses (N=4,475) were analyzed with binomial logistic regression analysis using "monitoring key rings" as the dependent variable and simultaneously inputted sex, age, living arrangement, social isolation, Instrumental Activities of Daily Living (IADL), and complaints of memory loss as independent variables. Interviews were also conducted in August 2014 of the staff members (N=12) of six community comprehensive support centers in the Ota Ward. The logistic regression analysis results indicated that women used the monitoring key rings 1.64 times more often than men, late elderly used it 4.39 times more often than early elderly, elderly living alone used it 2.14 times more often than elderly not living alone, non-isolated people used it 1.36 times more often than isolated people, IADL non-independent people used it 1.50 times more often than independent people, and people with complaints of memory loss used it 1.37 times more often than those without such complaints. On the other hand, the results of interviews indicated that elderly people living alone, those with worries, and relatively young and healthy elderly people were targets. The main targets of community comprehensive support centers were elderly individuals living alone and early elderly individuals. The utilization rate of elderly people living alone was high; however, that of early elderly people was low. They recognized that people registered with the system tended to have high anxiety, be relatively young and highly independent, and register after learning about the system from their peers or through neighborhood associations. Individuals who were female, late elderly, elderly living alone, non-isolated, IADL non-independent, or had complaints of memory loss were most likely to be registered with the key ring. The circumstance of registration which community comprehensive support centers recognize related to the low utilization rate of elderly people who are isolated. In the future, the system should be introduced to socially isolated as well as relatively young elderly people.