To provide an electromagnetic wave absorber having high efficiency in a high frequency band used for a radio transmission network of a cellular phone, a PHS, and a computer, and having performance as a building material.

Graphite and ferrite are mixed in a hard foaming resin body used for the building material such as phenol foam, isocyanurate foam, and urethane foam to obtain an electromagnetic wave absorbing foaming body having electromagnetic wave absorptivity, and having performance as the building material. When a mixing quantity of the graphite is set almost constant, a ferrite unmixed material has the highest frequency indicating a peak value of an absorption quantity. A material having high ferrite density, and having high finish density has a low frequency indicating the peak value of the absorption quantity. This electromagnetic wave absorbing foaming body is used by integrating a metalized film 11 into one surface of the electromagnetic wave absorbing foaming body A, integrating a metallic plate 12 into one surface of the electromagnetic wave absorbing foaming body A, and integrating cloth 13 into the other surface.