To make it possible to speedily obtain a lot for specific area in a city by the country without taking much time and a vast sum of money for purchasing the lot and to enable the redevelopment of the lot efficiently.

Urban residents provide lots for specific area 18 in a city by mutual agreement with the country in advance. The country divides the lots into sections 19 within a radius of 100 meters. Disaster prevention buildings 20 of earthquake and fire proof construction are constructed in the sections 19. A pair of buildings 20 are so constructed that they are opposed to each other, and they are connected with joint ridges 21. Then, residents in the peripheral area 23 of the area 18 also provide lots to the country in the same way as mentioned above, the country divides the lots, the buildings 20 are constructed, roads are constructed between the sections 19. The outskirts of the city are subsequently redeveloped in the same way.