PURPOSE: To prevent cracks from occurring in the connecting portion of column and beam by horizontally placing a plurality of reinforcing plates, each of which has an opening at its center, at required intervals in the connecting portion of column and beam and burying them in concrete placed.

CONSTITUTION: A plurality of reinforcing plates 5 such as steel plates, each of which has an opening at its center, are horizontally placed at required intervals in the connecting portion 3 at the intersection of column 1 and beam 2, and buried integrally in concrete placed in the connecting portion 3 of column and beam. Each reinforcing plate 5 is supported by securing to reinforcing steel plates 6 such as reinforcing bars. This constitution effectively prevents cracks from occurring in the connecting portion 3 of column and beam and improves the earthquake resistance.