PURPOSE: To form an incombustible wave absorber for high frequency by forming a composition prepared by mixing cement, light-weight aggregate, synthetic resin emulsion, carbon fibers and/or carbon graphite, and organic micro balloons together in water at a specific weight ratio.

CONSTITUTION: An electric wave absorber is formed by mixing 1-20 pts.wt. light-weight aggregate, 1-20 pts.wt. synthetic emulsion, 1-15 pts.wt. carbon fibers and/or 5-20 pts.wt. carbon graphite, and 1-10 pts.wt. organic micro balloons with 100 pts.wt. cement in water and molding the mixture in a prescribed shape. The shape is such that a plurality of mountainlike triangular structures 11 or pyramids 21 is formed on the surface of a substrate 1 composed of a single layer or plurality of layers and ferrites 2, 12, and 22 and metallic plates 3, 13, and 23 are provided on the rear surface of the surfaces 1. Therefore, an electric wave absorber which has a light weight and high fire resistance, can be easily worked, and can be effectively used for a wide range of frequencies can be obtained.