An antenna device includes a patch antenna serving as a first antenna; and a second antenna including capacitance loading elements, the capacitance loading elements being located above the patch antenna and also arranged separately in a predetermined direction. Also, an antenna device includes a patch antenna serving as a first antenna; and a second antenna including capacitance loading elements, the capacitance loading elements being located above the patch antenna, and a slit-like cutout part in a predetermined direction being formed in at least one of side edges of the capacitance loading elements.