Abstract: An electromagnetic absorbing element is comprised of an elongated rectangular body of dielectric material having a bottom portion attachable to an inner wall of an electromagnetically dark room, and peripheral elongated faces extending vertically from the bottom portion such that a set of the absorbing elements can be arranged in rows-and-columns on the wall. An electroconductive ink film is formed on the peripheral faces of body and has a gradually changing surface resistivity decreasing exponentially lengthwise of the peripheral face toward the bottom portion. The incident electromagnetic wave normal to the wall provided with the rows-and-columns of absorbing elements is absorbed by a lattice of the electroconductive films during the travel along the electroconductive films.