An antenna device and a beam direction adjustment method are provided. The antenna device includes an antenna element, a metal element, and a substrate. The antenna element and the metal element are separately disposed on the substrate at a preset distance. A ground point of the metal element is fastened on a pad of the substrate, and the ground point is on a side of the metal element close to the antenna element. A first reverse current opposite to an antenna current generated by the antenna element is obtained through coupling on the side of the metal element close to the antenna element, and a second reverse current opposite to a substrate current generated by the substrate is obtained through coupling at a lower part of the metal element that is in contact with the substrate.