An antenna device of the present disclosure includes: an antenna element that radiates a main lobe of a radio wave and one or more side lobes of the radio wave; and a radome through which the main lobe of the radio wave and one or more side lobes of the radio wave run. The radome has a focusing lens structure that focuses the main lobe of the radio wave that runs through the radome and a diverging lens structure that diverges the one or more side lobes of the radio wave that run through the radome.