A corrosion-free, weight-reduced, separation-free and rubber-adhesive vibroisolating device for absorbing vibration of radiator. The device includes: a rubber vibroisolating body inserted into and supported by a fixation jig formed on a vehicle body; a support portion integrally formed with the rubber vibroisolating body; and a plastic sheet body integrally injection-molded with the rubber vibroisolating body and provided with an inner protruder to be buried in the support portion and a support curvature for supporting an upper support bracket of the radiator.