31 rotates by virtue of the above mentioned construction elevation of the aperture 34 through which the water in the chambers r are drained is adjustable therefore it becomes possible to adjust the depth of the water in the chambers by rotating the inner tube thus it becomes easier to to adjust the natural frequency of sloshing which may be useful when fine adjusting the natural frequency an outer screw may be formed on an inner surface of the cylindrical sleeve 30 and an inner screw is formed on an outer surface of the inner tube 31 for a meshing engagement of them and for a spiral movement of the inner tube against the sleeve natural frequency of the building differs naturally according to the mode therefore geometry of the chamber retaining the liquid is determined so as to equate the sloshing natural frequency to the natural frequency of the building of the concerned mode further because the vibration restraining structure according to the present invention is compact the structure can be installed in any floor of a building walls of the building may be replaced by the vibration restraining structures for more space saving because the vibration restraining structure contains a considerable amount of.