Rain-gauge stations have been operated by many agencies, thus temporal and spatial characteristics of rain-gauge network have not been studied. We studied the observation density of rain-gauge network over Japan using available data observed by Japan Meteorological Agency (JMA), the River Bureau under Ministry of Land, Infrastructure, Transport and Tourism (RB-MLIT) and local governments (L-Gov). As a result of analysis of elevation, rain-gauge stations have been installed at a constant rate by each elevation class of the topography, and Japan has no rain-gauge stations over altitude 2500m. As a result of observation density by mesh analysis, approximately 70% of rain-gauge stations could observe rainfall data. In addition, we analyzed between DID and flood/drought disaster in recent years and observation density over Japan.