This paper shows a response control efficacy by using rotational inertia mass damper filled with magnetorheological fluid. Through a study on transfer function of the frequency domain, authors indicate the effective range of decreasing floor response acceleration by designing proper mass ratio. But, on passive control, they have the performance tradeoff between mass ratio and damping ratio, and there is a limit to decrease both floor response acceleration and response displacement. Then, authors suggest the skyhook-type semi-active control method. The suggested method makes it possible to decrease response on sympathetic vibration point and not to worsen response in high frequency range. Next, through a study on time history response, authors shows the skyhook-type semi-active control is effective to decrease both floor response acceleration and response displacement.