An antenna device includes transmitting units each of which includes elements arranged parallel to a baseline, wherein the transmitting units are arranged side-by-side in a first direction and stepwisedly with steps in a second direction in a first region and a second region, the first direction being perpendicular to the baseline, the second direction being parallel to the baseline, the first region and the second region being partitioned by the baseline, and transmitting units positioned more remotely from the baseline being positioned further in the second direction.