An antenna device includes an antenna base having a longitudinal direction, a first antenna element on the antenna base, and a pair of second antenna elements on the antenna base, the pair of second antenna elements being capable of transmitting and receiving radio waves in a higher frequency band than the first antenna element. In a planar view, when the antenna base is divided into four regions by a first line segment along the longitudinal direction and a second line segment orthogonal to the first line segment intersecting each other at the center point of the first antenna element, a region where one of the pair of second antenna elements is located is not adjacent to a region where the other of the pair of second antenna elements is located.