To easily set an aseismic wall by providing the lower end of a steel plate mounted from both sides of an existing beam downward in the lower surface of the beam, providing a steel frame on the lower part of the beam, and providing a bolt upward on the upper surface of the steel frame.

Steel plates 2 each consisting of a side plate 21, a bottom plate 22 and a shearing plate 23 are provided on both sides of a constructed existing beam 1, the side plates 21 are fixed to the side surface of the beam 1 by cross high strength bolts 11, and the shearing plates 23 are mutually fixed by a high strength bolt 23. After mortar 12 is press-fitted to the clearance between the beam 1 and the steel plate 2, the bolts 11, 24 are mainly fastened. A steel frame 3 constituting an aseismic wall is provided on the lower surface of the beam 1, so that its stud bolts 31 are provided on both sides of the shearing plate 23. Further, a ladder bar is provided between the beam and the steel frame 3, a form is further provided, and mortar 32 is then filled therein. According to this, the aseismic wall can be set without driving a number of anchor bolts.