An antenna apparatus is provided with a first antenna element, a second antenna element, a first ground element, a first ground plane and a second ground plane each formed by a conductive pattern. The first antenna element and the second antenna element are electrically connected by a first through-hole, and also form a first capacitive coupling portion in which they partially overlap across a substrate and are capacitively coupled. Such a configuration enables the antenna apparatus to be realized at low cost, since an antenna can be formed with only a substrate and conductive patterns, without requiring additional elements such as sheet metal. The antenna apparatus also can be reduced in profile and size, since only the conductive patterns are formed on a first surface and a second surface of the substrate, and there are no members that project significantly from the plane of the substrate.