An electronic device includes a case and an antenna provided on the case. The electronic device also includes the following. A first adjuster is formed of a metal material. The first adjuster (i) is provided in a position in which one end side is provided to come into contact with or to be near the antenna and (ii) in which the other end side is provided in the case. A cylinder is included in the case, is formed of a metal material, and the other end side of the first adjuster is inserted therein. A second adjuster is formed of a dielectric material and is provided in the cylinder to exist between the cylinder and the first adjuster.