A composite material which comprises an elastomer or vulcanized rubber and particles of a high−density material, such as tungsten, evenly dispersed therein, wherein the contents of the elastomer or vulcanized rubber and the high−density particles are 35 to 50 vol.% and 50 to 65 vol.%, respectively, based on the whole composite material, and the high−density particles have a particle composition comprising 60 to 80 vol.% coarse particles having a particle diameter of 10 to 100 µm, 10 to 20 vol.% medium particles having a particle diameter of 3 to 6 µm, and 10 to 20 vol.% fine particles having a particle diameter of 1 to 2 µm, the spaces among the coarse particles being filled with the medium particles and fine particles. The composite material is excellent in flexibility and processability and is suitable for use as a radiation−shielding sheet material, weight member, vibration−damping material, balancing member, radiating material, and shot material.
