PURPOSE: To carry out the footing construction work together with a piling work concurrently by using a sheet-form substance as the outer mould member, forming a hollow at a tube-form inner mould position in a rod reinforcement position, and incorporating the rod reinforcement and a footing after the concrete is hardened.

CONSTITUTION: The part where the piling is finished is cut and excavated to expose pile heads 5 so as to set the pillar positions, and a base reinforcement 4 is placed to set an anchor 9 and the like. And on the base reinforcement 4, a cylindrical inner mould 8 with bottom is provided, and a concrete 11 is placed to make the position of the reinforcement 13 in a hollow. An outer mould made of a sheet is assembled to surround the whole body and the concrete 11 is placed in the mould. After the concrete is hardened, a pipe support 6 and round steel pipes 2 are removed to construct a footing having a hollow. Consequently, the work can be carried out concurrently with the piling work, the term of the work is reduced, and the cost can be also reduced.