PURPOSE: To obtain a vibration isolating effect against an earthquake by forming the end of a shaft engaged at its one end with the bottom of a housing in a semispherical shape or providing a rotatable sphere at the end, and forming the contact face of a tray in a curved state.

CONSTITUTION: The contact surface 3 of a tray 2 in contact with the end 1A of a shaft 1 formed in a semispherical shape or a sphere 8 engaged with the end 7A of a shaft 7 is formed in a curved state low at its center and high at its outer periphery. The gradient of the curved surface is so set that, if a moving distance is increased when the end 1A or the sphere 8 is moved along the surface 3a, its frictional resistance is increased. With this structure, even if a large earthquake wave is generated, the tray 2 is not moved to obtain a sufficient vibration isolating effect. The moved end 1A presses a housing 4 to be returned to its original position. In the case of the ball 8, it is automati cally returned to a center by its own weight of the housing.