To provide a vibration isolation device which has vibration isolation performance effectively enhanced by preventing the occurrence of surging and reducing a natural frequency.

The vibration isolation device includes a spring unit 12 housed in a housing hole 14 formed in an elastomer pad 11 made of a foamed polyurethane elastomer, the spring unit including: a compression coil spring 20 having a free length larger than a thickness of the elastomer pad 11; and a pre-compressing means 16, 18 that preliminarily compress the compression coil spring 20 in a compression amount to give a natural frequency smaller than that of the elastomer pad 11 and maintain the preliminarily compressed state. In the housed state, the spring unit 12 is disposed in such a manner that a supporting face 44 of the spring unit 12 exposes outside and the compression coil spring 20 is in contact with an inner circumference face of the housing hole 14 when vibration is input.