An antenna device usable in a radio apparatus having a printed board includes a ground conductor provided in the printed board, a fed partial element, a first branch element and a second branch element. The fed partial element is shaped as an area including a feed portion near an end of a first side of the area facing a side of the ground conductor, and a first branch portion and a second branch portion each near a portion of a fringe of the area other than the first side. The fed partial element may be fed at the feed portion. The first branch element branches off from the first branch portion and is folded back in a direction approaching the feed portion. The second branch element branches off from the second branch portion and is shaped in a direction close to the direction of the first branch element.