To enhance vibration mitigating effect by a method wherein vibration mitigation control is secured by limiting to an active vibration mitigating device, simplification is performed using a diagonal member as an independent frame face, a main building is constructed on the large beam of an independent frame, the top part of the main building and the large beam are interconnected by the active vibration mitigating device and vibration mitigating effect is enhanced.

The vibration mitigating structure has an independent vibration mitigating frame face 2 or an independent vibration mitigating frame, and in order to further secure vibration control, a vibration mitigating device interconnected to the independent frame face or the independent frame is constructed as an active vibration mitigating device 3 provided with a control computer 4 and a response sensor 5. In addition, a diagonal member is provided as the independent frame face, the active vibration mitigating device 3 is inserted in the diagonal member, and both the ends of the diagonal member is pin-connected to a main building to simplify constitution. In case of a new built building, the independent frame is constructed on the outer circumference of the main building, several independent layers of the main building are constructed on the large beam of the independent frame, and the uppermost part of the main building is interconnected to the large beam of the upper story of the main building by the active vibration mitigating device 3 to suppress fluctuation of earthquake.