The epidemics had been prevalent during the Nara period in Japan. Among these infectious diseases, some types were originated from Japan and some new ones were imported from the Asian continents. This thesis is a research which based on the records of epidemics written in Shoku-Nihongi. According to epidemiological analysis, the time and space distributions of epidemics during the Nara period are made clear. Based on these distributions, the contagious patterns of the diseases came from the Asian continents, and the prevalent space of the inherent infections is demonstrated.