Abstract
　The heavy rain which swept over the Nagasaki districts on 23 July 1982 killed 299 persons and damaged so seriously to Nagasaki City and its vicinity. Total cost of destruction caused by the flood was 350 billion yen. The local government set up the committee to deliberate the urban safety planning in Nagasaki districts.The damaged areas were rebuilt and the population's safety was improved according to the presented plan.Following up on the reconstruction process, river improvements, construction of roads and warning system were worked out considerably. However, urban planning dealing with the prevention of disasters is not improved so much. In this paper, the urban safety planning in the Nagasaki districts and its achievement are investigated by interviews with local governments and data on the Nagasaki flood disaster.

【キーワード】：長崎水害，都市水害，復興，都市計画，防災施設
Kew word : Nagasaki flood disaster, urban flooding, reconstruction, urban planning, disaster prevention facility

*長崎大学工学部社会開発工学科
Department of Civil Engineering, Faculty of Engineering, Nagasaki University