An antenna device has a first antenna element supporting a low frequency band and a second antenna element supporting a high frequency band. The first antenna element and the second antenna element are disposed so as to face to each other, on the wiring board of a radio device, and at positions separated from each other by a predetermined distance. The distance between the first antenna element and the ground of wiring board is longer than the distance between the second antenna element and the ground of the wiring board. The antenna device supports two frequency bands with the first antenna element and the second antenna element.