In Toyota where our hospital plays a role of a municipal health provider, population will increase slightly, but aging will quickly progress in coming 20 years. In this paper, we envisaged the picture of future health services to be provided by our hospital based on the age-specific population movement date by the five-year age categories in the “Regional Population Projection for Japan: 2010-2040”, which was worked out on trial by the National Institute of Population and Social Security Research. The population was divided into four ranks, “juvenile”, “production-age”, “young-old”, and “old-old”. We assessed the types of prevailing disease in the year 2025 when the ages of all baby boomers are expected to exceed 75 years.　　The population in Toyota will slightly decrease along with a decrease in the number of people in juvenile and production-age ranks until 2035. In contrast, the population of those in the young-old and the old-old group population ranks will increase by 1.2 times and 2.4 times, respectively. Since about 12% of the old-old group is expected to be inpatients of our hospital, with the increase in the old-old group, the number of the patient to be discharged from our hospital will also increase. In the year 2025 when the number of obstetrics patients as well as new born infants will decrease in proportion to the reduction in the population. On the other hand, all types of neoplasm, cardiovascular disease, digestive disease, respiratory disease, and injury, which are common in the old-old group, will increase.　　Given that almost 80% of the patients discharged from our hospital are Toyota residents, the total number of patients to be discharged from our hospital in 2025 could be 20,000. When the average length of hospital stay in 2012 is applied to calculate the rate of the hospital bed occupancy rate, it would be 105% in 2025. It means that shortage of sickbeds will occur in our hospital. To cope with their problem, it will be necessary to shoten the length of hospitalization.