Antenna device

A feed element for feeding power is disposed on a substrate. A first parasitic element is disposed at a position different from a position of the feed element as viewed from above and is electromagnetically coupled with the feed element. A dielectric member is disposed at a position at which the dielectric member at least partially covers the feed element and the first parasitic element as viewed from above. A conductive pattern is disposed on a surface of the dielectric member which faces the feed element at a position at which the conductive pattern matches the first parasitic element as viewed from above. The dielectric member is supported by the substrate as a result of the conductive pattern being electrically connected to the first parasitic element.