The investigation on damages which are the causes of changes in the atom-bombed cities, Hiroshima and Nagasaki which had to undergo striking changes after the war, shows that in Hiroshima, the damaged area extended to the whole city, while, in Nagasaki it was 30 per cent of the centre of the city. 92 per cent of the houses in Hiroshima were damaged, while they were 40 per cent in Nagasaki. ... [Show full abstract] Suffered people of the former reached to 92 per cent, on the other hand, in the latter 44.7 per cent. The difference of damages between the two cities are considerably large.Right after the war, 39.8 per cent of people remained in Hiroshima city, on the contrary, in the latter 52.8 per cent remained. That shows the number of the remainders of both cities were close. According to the difference of the centres of the bombing between two cities, in Hiroshima almost all of the suffered people gathered in the circumference of the city, on the contrary, in the latter, gathered in the centre part of the city.At first, 60 per cent of those suffered people left the city and most of them settled in the villages among mountains. But recently, 62 per cent of their living place are found in the city and 17 per cent live in the outside of the city.After the place was bombed, we saw the sudden increase of the population around the centre of the bombed place. At present, the population became a half of what it used to have before the war. 80 per cent of the houses that were in the city before the war, have been rebuilt. Housing problems are gradually relieved in numder, but in quality, the problems can not be dissolved easily.