To protect a computer or a medical electronic equipment against interference induced by arriving radio waves with a composite radio wave absorbent by a method wherein the composite radio wave absorbent is surrounded with a conductor and formed like a structure such as a lattice, a honeycomb, a tooth shape, a triangle or a circle that recesses and has a hollow base.

A lattice composite radio wave absorbing skeleton 3 is formed through such a manner that synthetic resin phenolic resin cellular material compounded with radio wave absorbing ferrite Fe3O4 is poured into a molding die for the formation of a composite radio wave absorbent having a hollow base suitable for absorbing arriving radio waves. The inner surface of an assembling outer frame is composed of a large number of aluminum plates arranged in lattice. Conductor fibers are cut, bonded together with the same material with a composite radio wave absorbent, 1, and bonded to the base in the direction in which radio waves arrive. A molding operation is carried out so as to surround a composite radio wave absorbent 1, the radio wave absorbent 1 enhanced in return loss can be obtained, and an electronic equipment or the like can be protected against interference by arriving radio waves with the radio wave absorbent 1.