Since the ITER machine supports are designed to provide flexibility for the horizontal movement so as to allow mutual displacement of the various tokamak components operating at different temperatures. In addition, seismically isolated structure is required to assure the structural integrity under the seismic loads over the acceleration of 0.2 g. This paper outlines the dynamic response of the tokarnak structure with flexible machine supports, and describes the validation test of laminated rubber bearings used for seismic isolation and the plan of vibration test using a scaled tokamak model. The engineering design of the International Thermonuclear Experimental Reactor (ITER), which is a DT-burning tokamak machine, has extensively progressed under international collaboration of the European Union, the United States, the Russian Federation, and Japan (I). The core of ITER tokamak is composed of superconducting coils, a vacuum vessel and in-vessel components, which are operating at different temperatures ranging from cryogenic temperature to several hundred degree C. Therefore, the machine supports composed of multiple plates were adopted to provide flexibility for the horizontal movement so as to accommodate mutual displacement of the tokamak components, while keeping high rigidity in the vertical direction. According to the design guideline, the ITER tokamak was designed to withstand the IAEA SL-2 class seismic acceleration of 0.2 g. In addition, applying seismic isolation to the tokamak building was also studied for severe seismic loads over 0.2 g. Parameter studies on seismic isolation using a simple mass-spring model have shown that the laminated rubber bearing with an oscillation period of 3 m 4 set can be adequate to reduce the response acceleration acting on the tokamak components under seismic events. In this case, however, a large rubber bearing with a diameter of more than 1 m is required to support a high vertical compression of more than 100 kg/cm2. In order to verify the feasibility and applicability of this large and high compression rubber bearing, the sub-scaled rubber bearings with different diameters from 0.2 m to 0.7 m were fabricated, and