PURPOSE: To improve the habitability of a building at the time of an earthquake of middle or small magnitude by providing a vibration-damping brace which is constituted of a square steel pipe and which is constituted of a steel of extremely low-yield point provided over a predetermined length in the middle of members of a frame constituted of a column and beam.

CONSTITUTION: A vibration-damping brace 3 constituted of a square steel pipe is incorporated into a frame formed from a steel column 1 and steel beam 2, and a steel of extremely low-yield point is incorporated into the middle portion 3a of the brace 3 over a predetermined length LB. Next, since the steel of extremely low-yield point is provided in the middle portion 3a, deformation of the brace after the steel has yielded can be concentrated in the portion 3a and even if the brace 3 has a uniform elastic rigidity over the entire cross section, after the portion 3a has yielded, higher plastic deformation energy can be produced as compared to a case in which a steel of extremely low-yield point is provided in the whole cross section. In the case of an earthquake, the brace 3 yields instantly so that the vibration of a building at earthquakes can be limited, and hence a highrise building which has small response to earthquakes can be provided and habitability thereof can be improved.