An antenna device includes: a ground upper layer substrate of a dielectric substrate forming a first ground part and a second ground part disposed at a predetermined distance from the first ground part; a ground lower layer substrate of a dielectric substrate forming a third ground part and a fourth ground part disposed at a predetermined distance from the third ground part; and an inner layer substrate of a dielectric substrate forming a fifth ground part. The ground upper layer substrate, inner layer substrate, and lower layer substrate are laminated. The first ground part and third ground part are electrically connected. The second ground part and fourth ground part are electrically connected. The antenna device further includes: a chip antenna disposed on the ground upper layer substrate, transmitting and receiving electromagnetic waves; and an adjustment component electrically connecting the first ground part and second ground part, and adjusting antenna characteristics.