PURPOSE: To prevent deformation due to load on an external wall by providing respective bolt holes in the center of the vertical piece of a first L-shaped metal fitting, the vertical piece of a second L-shaped metal fitting, and a pair of the horizontal pieces of a box shaped metal fitting, and threadedly fixing a bolt into these bolt holes.

CONSTITUTION: A first L-shaped metal fitting 1 is formed so that the horizontal piece is set as an external wall fitting part 1a and a bolt hole 1c is provide in the center of the vertical piece 1b. A second L-shaped metal fitting 2 is formed so that the horizontal piece 2a is piled on the external wall fitting part 1a in a posture opposing to the first L-shaped metal fitting 1 and a bolt hole 2c is provided on the vertical piece 2b. A box shaped metal fitting 3 is formed so that the upper face is set as a fitting part 3a to a beam and a pair of bolt holes 3c are provided on a pair of the opposing lateral pieces 3b. Next, the pair of bolt holes 3c are conformably arranged to the respective bolt holes 1c, 2c of the metal fittings 1, 2, and they are fixed with a bolt 4 and a nut 5. Consequently, because vertical force applied on the external wall fitting part and the beam fitting part can be received with the first and second metal fittings so as to prevent deformation.