Reduction in medical expenses which keep being increased is a problem of all the countries. In this paper, it was considered using System Dynamics to understand how utilization of digital and ICT (Information and Communication Technology) impacts on medical expenses in Japan, what the point is and when it appears. There is a study by which control of a disease and the reduction of medical expenses shows that there is a significant relation. There is a study that the disease education for which digital and ICT was utilized indicated significant cost benefit compared with existing disease education. Utilization of digital and ICT is expected that it is a useful tool for a problem solution in the healthcare field (healthy, medical treatment and the nursing field) from the research results. These approaches which utilize digital and ICT for a problem solution of the healthcare field is called “health Tech” or “digital health”. Utilization of digital and ICT to the problem solution in healthcare field and a system which is collecting data from human body, analyzing them with data mining or machine learning method and the analysis results are feed backed to individuals as advices is called a smart health in this paper.