To mutually connect a plurality of pilasters by simple constitution, to reduce bending moment resulting from the load of a building working to a slab or a footing beam with pilasters and to decrease the concrete thickness and areas of reinforcements of the slab or the footing beam.

In the foundation structure of the building with a plurality of the pilasters 21 connected by the slab 23, anchor bolts 21A projected from the top faces of a plurality of the pilasters 21 are connected mutually by head connections 30.