In an antenna device, first and second vertically-polarized antennas are disposed at respective horizontal end portions of a substrate. A first ground pattern functioning as a ground plane of the first antenna and a second ground pattern function as a ground plane of the second antenna are disposed on the substrate. An intermediate pattern is located between the first ground pattern and the second ground pattern and functions as a horizontally-polarized non-feed element for the first antenna and the second antenna. The phase control part controls a phase difference between a signal of the first antenna and a signal of the second antenna by changing at least one of a phase of the signal of the first antenna and a phase of the signal of the second antenna. The combining portion combines the signals after the phase control part controls the phase deference.