PURPOSE: To obtain a radio wave absorber excellent in a structural strength and a radio wave absorbing property by a method wherein the absorbent is composed of layers such as a supporting layer formed of silicon carbide fiber impregnated with resin, a radio wave absorbing layer containing carbon particles, and a radio reflective layer.

CONSTITUTION: An absorbent layer 3 is provided to one side of a supporting layer 2 of a composite material composed of silicon carbide fiber impregnated with epoxy resin. The absorbing layer 3 is constituted in such a manner that the mixture of hollow or ball-shaped carbon particles and epoxy resin is made to fill a honeycomb core as it is fluidized and set. A reflective layer 4 consists of an aluminum foil or aluminum plate. By these processes, a radio wave absorber excellent in a structural strength and a radio wave absorbing property.