An antenna device includes a first antenna element made of a conductive metallic plate and formed in a shape of a meander; a second antenna element made of another conductive metallic plate and formed in another shape of a meander; and a sealing material which is made of a high-dielectric material and is configured to seal the first and second antenna elements by the sealing material, wherein the first antenna element is arranged in parallel with the second antenna element, and wherein the first and second antenna elements are embedded inside the sealing material by insert molding.
