To improve the shape holding property for a long time by mutually welding first foam grains composed of foams of a thermoplastic org. polymer and conductive layer formed their surfaces with second foam grains composed of foams of a thermoplastic org. polymer.

The wave absorber is easily made by forming a melt of a mixture composed of first and second foam grains e.g. heated in a die into desired shaped molding. The first foam grains composed of foams of a thermoplastic org. polymer and conductive layer formed their surfaces. This layer is made of a conductive powder such as carbon black, graphite, metal powder, etc., and has a mean thickness of approximately 0.5-10μm, esp. 1-5μm. The second foam grains are welded to the first grains to elevate the bond strength of the grains and uses foams of various thermoplastic org. polymers.