Abstract
As health related big data, there are DPC and National database（NDB）in Japan. Annually the former gathers over 11 million discharge data and the latter accumulates more than 1.7 billion claim data only for medical services. The recent development of information technology has made it possible to process these big data easier and the government tries to advance its use for health policy making. Compared with similar data of other countries, the DPC and NDB are very superior for its exhaustiveness and detail. The advance in use of these data is expected to contribute the further development of health service research in Japan. To do so, we have to train more human resources for health related big data analyses.
