In this article, we describe the history and current state of psychosomatic medicine (PSM) in Japan and propose measures that could be considered based on our view of the future prospects of PSM in Japan. The Japanese Society of PSM (JSPM) was established in 1959, and the first Department of Psychosomatic Internal Medicine in Japan was established at Kyushu University In 1963. PSM in Japan has shown a prominent, unique development, with 3,300 members (as of March 2016), comprised of 71.6% of medical doctors including psychosomatic internal medicine (PIM) specialists, general internists, psychiatrists, pediatricians, obstetricians and gynecologists, dentists, dermatologists, and others. Most of the non-physician members include psychology and nursing staff specialists. The Japanese Society of Psychosomatic Internal Medicine (JSPIM), founded in 1996, is another major society with more than 1,200 physicians that is mainly composed of internists. The first joint congress of the five major PSM societies from each field was held in 2009. They included the Japanese Society of Psychosomatic Medicine, Psychosomatic Obstetrics and Gynecology, Psychosomatic Pediatric Medicine, Psychosomatic Dental Medicine, and Psychosomatic Internal Medicine. Several subdivided societies in related medical fields have also been established for cardiovascular, digestive, dermatological, and oriental medicine and for eating disorders, pain, fibromyalgia, stress science, behavioral medicine, and psycho-oncology. JSPM and JSPIM participate in international activities including publishing BioPsychoSocial Medicine (BPSM) and the establishment of a sister society relationship with the Germany College of PSM. PSM in Japan has adopted a variety of professional psychotherapies, including transactional analysis, autogenic therapy, and cognitive behavioral therapy. Mutual interrelationship has been promoted by the Japanese Union of Associations for Psycho-medical Therapy (UPM). Although PSM in Japan is functioning at a high level, there remain areas that could be improved. Among the 81 medical schools in Japan, just eight university hospitals have an independent department of PSM and of 29 dental schools only three dental university hospitals have a department of psychosomatic dentistry. Further accumulation of evidence regarding the mind-body relationship in clinical and basic science that is based on the latest advanced technology is necessary. The psychosomatic medicine community needs to make an even greater contribution to meeting the needs of modern society. The possibilities for the future development of PSM in Japan must be widely discussed.