PURPOSE: To eliminate trouble with the mutual interference of wave motions by forming a structure closely contacting with a three-dimensionally complicatedly bent boundary face from a medium and a permeable medium.

CONSTITUTION: In a wave motion interruption device to eliminate wave motions resulting from interference of propagating wave motions and the conversion of wave energy to heat energy, a medium 1 to propagate original wave motions and a permeable medium 2 composed of a mixture of different kinds of viscoelastic substances, e.g., clay, sand, etc., and fine solid particles are provided, and a structure closing contacting with a three-dimensionally complicatedly bent boundary face 13 is formed out of the medium 1 and permeable medium 2. Since plural wave motions can be mutually counterveiled and varnished or damped in the permeable medium 2, troubles with the mutual interference of wave motions can be eliminated.