The aim of this study is to clarify experimentally the vibration behavior of rigid body placed on dense sand ground surface in resonant condition. The rigid bodies with variable mass, inertial moment and base size were prepared, and their vibration behavior was observed in a series of forced vibration tests. From the observed behaviors, the resonant and natural frequencies and amplification factors were analyzed. It was found that the natural frequency and amplification factor in resonant condition are dependent on the contact pressure of footing.The stiffness coefficients of springs modeling the interactive mechanical behaviorbetween rigid body and ground were assessed from the analysis of coupled horizontal and rotational vibrations. The influence of base pressure and base size on the spring coefficients is also discussed.