A vibration damper includes two materials, each being formed of a metal sheet having a rubber- or synthetic resin-base viscoelastic polymeric layer or layers formed on one or both sides, which are arranged in opposition to each other through said viscoelastic layers and bonded together with the use of a hot-melt-adhesive synthetic resin layer having a high melting point. Alternatively, one of said materials is arranged in opposition to another metal sheet through said vicoelastic layer or layers and bonded thereto with the use of said hot-melt-adhesive synthetic resin layer. A soundproofing structure using such a vibration damper is also provided.