Concrete foundation structure and construction method for same

Provided are a concrete foundation structure and a construction method for same that can rigidly fix a precast concrete foundation to the ground.　A concrete foundation structure 10 comprises a precast concrete foundation 16 that has a projection 30 embedded in the ground G. An anchor plate 20 is placed inside a drilled hole 18 provided in the ground G, and the precast concrete foundation 16 and the anchor plate 20 are coupled by a coupling member 22. A backfill section 24 is formed inside the drilled hole 18 with backfill material 94 that includes solidification material and soil. A fill layer 26 is formed between the precast concrete foundation 16 and the backfill section 24 with fill material 96 that includes solidification material. The precast concrete foundation 16 has a through hole 42 into which the coupling member 22 is inserted, and the fill material 96 constituting the fill layer 26 is loaded through the through hole 42.