PURPOSE: To construct a concrete strip footing for a building easily and correctly, and increase a strength at a position where vertical force of an upper load is applied largely at a part of the constructed strip footing especially where a column is placed.

CONSTITUTION: Foundation cylinder bodies 4 opening at both of upper and lower ends and having a throughhole 6 are disposed at a plural positions of a broken stone foundation 3. A pair of formworks 8 for concrete strip footing are disposed facing each other between adjacent foundation cylinder bodies 4, and reinforcements 9 disposed in a facing space of the formworks penetrate the throughholes 6 in the foundation cylinder bodies 4. Concrete is placed in the facing space of the formwork 8 and inside the foundation cylinder bodies 4.