PURPOSE: To prevent an elastic body from degradation and exfoliation for improving durability of a spring mounting insulator device by attaching the elastic body absorbing inputs with shearing deformation between the car body side and the wheel side to form a communicating space extending from the upper surface to the lower surface of the elastic body.

CONSTITUTION: An elastic body 8 is provided between an outer tube 7 at the wheel side and an inner tube 9 at the car body side. The outer tube 7 is formed on the upper end with an upper spring seat 6 provided on the lower surface with an elastic buffer body 21 and on the upper surface an elastic buffer body 22 for a stopper regulating the ascend of the outer tube 7. Said elastic body 8, for example, is provided with communicating space extending radially of the inner tube 9 from the upper surface to the lower surface on three positions at an angle of 180° to each other. Thus, dust attached to the upper surface of the elastic body 8 and rain water or the like sprashed on the upper surface of the elastic body 8 during travelling are flowed down through the communicating space 23. Thus, the elastic body 8 is prevented from degradation and exfoliation to improve durability of a suspension system.