Provided is an antenna device with a simple configuration and in which it is possible to control the directivity in various directions. An antenna device according to the present invention is provided with: an array antenna that includes at least one antenna element disposed on a first surface of a substrate and that forms beams in respective directions having a plurality of angles including a first angle relative to the first surface of the substrate; and a side wall that is provided on at least a partial periphery of the at least one antenna element and that refracts, in a direction along the substrate, a first beam in the direction having the first angle.