日本國民健康保險制度，與其他社會保險相較下之特色為：具補充性及排他性；具濃厚的社會福利性質，社會保險色彩較淡薄；再者，隨老齡化社會之到來，老齡者被保險人之比率極高；退職者醫療制度融入國民健康保險；與老人保健接軌；與看護保險制度併行。 在權限分配上，國民健康保險事務，原則上為國家事務，且由國家及地方共同執行，不過亦有地方自治團體之自治事務。至於費用負擔方面，主要係由國民健康保險費（或保險稅）、國庫及被保險人自付額或部分負擔共同支應。

The features of legal system of national health insurance in Japan are exclusive, like social security, elderly people is high rate, medical care system of retired employee is included, medical care system of elderly people is connected with national health insurance, national health insurance and care insurance system are carried out side by side. In distribution of authority of national health insurance, lots of these are belonged to the country in principle, but the execution of these are country & self-government, there are also belonged to the local government at the same time. The further, the funding is from health insurance fee (or tax), national treasury，and cost sharing.