PURPOSE: To shorten the term of work, and to equalize each type of occupation of construction for a prolonged term by simultaneously advancing the construction of an outer-circumferential section underground body and a ground body and the finishing of an outer-circumferential section body and the construction work of an inner-circumferential section body respectively.

CONSTITUTION: Two stripes of landslide protection walls 1, 1 along the outer circumferential section of a building are executed through the method of trench-cut construction in approximately the clearance of approximately one spun of the building, and open-cut while successively reinforcing the landslide protection walls 1 by shores 11. Outer-circumferential section underground bodies 2 are built to the underground excavating section while outer- circumferential section ground bodies 3 are built in constitution, in which travelling is enabled on a rail 12 for movement laid on the ground while crossing the upper sections of the bodies 2. Supporters 13 are mounted at a stage when these construction is to some extent advanced, temporary roofs 6 are installed among the supporters and the outer-circumferential section ground bodies 3, and the outer-circumferential section under-ground bodies 2 are executed in an all-weather type. The bodies 2 are completed up to a ground level, and the similarly completed outer-circumferential section ground bodies 3 are made to travel, and build successively under a superposed state.