A vibration damper with improved durability achieved by preventing stress concentration in a partition wall portion to avoid an excessive increase in strain in that portion. An intermediate cylinder member (20) is fitted to the inner peripheral surface of an outer cylindrical member (16), and a rubber elastic body (22) is arranged between a mounting member (18) and the intermediate cylinder member (20) to elastically connect them. A first and a second hollow cavities are formed in those regions of the rubber elastic body (22) which correspond to regions in the inner peripheral side of a small diameter portion (20B) of the intermediate cylinder member (20). Partition wall portion (22D) for partitioning the hollow cavities from each other are formed in regions of the rubber elastic body (22) between the first and second hollow cavities. The partition wall portion (22D) of the rubber elastic body (22) has both ends (23) fitted into a pair of openings (44, 46) of the intermediate cylinder member (20) so as to project from the openings (44, 46) toward the outer cylinder member (16).