This study aims to show the causative factors of suicide among the elderly (over 65) in Mie Prefecture, and to discuss the prevention of the factors contributing to suicide in the elderly group. We obtained an agreement from the Mie Prefectural Police Headquarters and investigated all inquest records collected between 1996 and 2002 in Mie Prefecture and focused on suicide in the elderly group. During the test period, the number of suicides in the elderly group was 842. In causative factors, the two major causative factors of suicide were "suffering from physical illness" and "psychiatric disorders". In particular, the three most frequent physical illnesses were "cardiovascular disease", "orthopedic disorder", and "digestive organ disease", and these physical illnesses are mentally stressful, and thus have a psychiatric component, the same as psychiatric illnesses do. Consequently, it is concluded that improvements in the home nursing and mental health care should include the prevention of suicide in the elderly who "suffer from physical illness" and "psychiatric disorders" to prevent suicide. In addition, medical staff and the general public should be educated on the factors that can influence elderly persons' mental condition, and should be cautioned to observe elderly persons for suicidal signs and symptoms.