Recently many types of structure controlling device for wind and earthquake disturbances have been developed for the purpose of improving the residential habitability. The authors developed the Tuned Active Damper (TAD) consisting of multi-stage-pendulum type Tuned Mass Damper (TMD) and controlled-driving device that drives the TMD's mass more effectively. This TAD was applied to the Yokohama Landmark Tower that is the tallest building in Japan, and moreover the vibration test and actual wind response observations were carried out. As a result of these tests and observations, it was confirmed that (1) TAD improves the equivalent structural damping factor to more than 10% in terms of the damping constant. (2) TAD reduces the structural vibrations in a strong wind to less than 40% of the case without control. (3) The performance of TAD is the same as that expected according to theory.