horizontal vibration can be done by adjusting only one portion adjustment of the characteristics adapting to the vibration characteristics of the construction or building becomes easier it will be appreciated that while the coil spring 11 is a primary element for producing resistance against pivotal movement of the pivotal plate 10 and the pendulum 14 is employed as an element for adjusting the anti vibration characteristics it is possible to employ only pendulum 14 for producing the resistance against pivotal movement of the pivotal plate 10 and for adjustment of the anti vibration characteristics also while the resistance against pivotal motion of the pivotal plate 10 is provided by the coil spring 11 it is possible that the pivotal plate can be coupled with an active drive such as a motor hydraulic actuator and so forth for actively suppressing vibration of the construction next discussion will be made of the second embodiment of the hydrostatic anti vibration system according to the present invention it should be noted that like reference numerals to the foregoing first embodiment denote like elements as shown in fig4 two intermediate tank portions 2 are positioned in the recessed central portion of the main tank body 4 surrounded by the vertical extension 5 two spaces defined in each intermediate tank portion 2 by the respective partitioning plate 7 are communicated with respective mutually opposing portions of the vertical extension 5 through ducts 3 to cause fluid flow in reversed phases therefore the fluid forces in two spaces of one intermediate tank portion 2 are opposite in phase to the adjacent portions of the vertical extension 5 thereby certainly avoiding mutual cancellation since the intermediate tank.