There are provided a high-permittivity dielectric raw material, an antenna device using the raw material and being useful as, especially, the built-in antenna device of a portable phone; a portable phone which can be reduced in weight, thickness and size, with an antenna radiation efficiency improved, and an electromagnetic wave shielding body for effectively shielding electromagnetic wave from an electric cooker.A dielectric raw material A having carbons dispersed in a silicone rubber base material 1, wherein, in any one of dielectric raw materials A, 1) containing 150 to 300 pts.wt. of carbons per 100 pts.wt. of silicone rubber, 2) formed by crosslinking and molding a mixture of non-crosslinked silicone rubber, non-crosslinked organic polymer and carbons, and 3) formed by combining and blending at least two kinds of carbons having different shapes and selected from spherical carbon 2, flat carbon, carbon fiber with a specific aspect ratio, carbon nanotube and conductive carbon 3, carbons are unevenly distributed in a silicone rubber base material 1 or carbons are contained with at least part of them contacting each other.