To simply adjust places of set heights of an anchor bolt and a reinforcing plate, and to finely adjust the height of the reinforcing plate when concrete is placed in a foundation structure with the anchor bolt.

A jig 50 for the execution of works of the foundation structure with the anchor bolt has anchor plates 60 and screws 80 for adjusting the reinforcing plates mounted to the anchor plates 60. The anchor plates 60 are held to upper sections of opposite forms 30, and hold the upper end of the anchor bolt 25. The screws 80 for adjusting the reinforcing plates are made to abut against the reinforcing plates 26, and the height places of the reinforcing plates 26 to the anchor plates 60 are adjusted.