FOUNDATION CONSTRUCTING METHOD

PROBLEM TO BE SOLVED: To easily construct a foundation which has sufficient vertical and horizontal support forces, even in a narrow site while restraining an adverse effect on surrounding areas. SOLUTION: Composite bodies 13 are each constructed by driving a micro-pile 12 into an improvement column 11 built in the ground 2 by a high-pressure injecting/agitating method, and the composite bodies 13 are sequentially constructed along a planning line of a foundation, to thereby construct a sequential wall 1. Next, improvement columns 17 by the high-pressure injecting/ agitating method are built in the ground within the sequential wall 1 in all directions, to thereby develop an improved batholith 4. Thereafter, the ground within the sequential wall 1 is bored down to the improved batholith 4 to form a shaft 3, and then a hooting 5 is constructed on the improved batholith 4. Further, a midpoint of a column base 7 of a structure built on the footing 5 is rigidly connected to a shaft head of the micro-pile 12 by means of a connecting plate 20.