A sound insulating device having a shock absorbing mechanism put between an upper material and a lower material, for absorbing vibrational impact sounds wherein the shock absorbing mechanism comprises a spring mechanism that elastically deforms under the effect of an impact load thereby absorbing vibrational impact sounds, and a shock absorber disposed between the spring mechanism and the upper material or the lower material, the shock absorber having a weakened portion that deforms elastically prior to the elastic deformation of the spring mechanism. Vibrational light weight impact sounds as well as vibrational heavy weight impact sounds can be absorbed by absorbing the vibrational light weight impact sounds by the elastic deformation of the weakened portion, without deteriorating the habitability.