An antenna device (100) according to the present invention includes a primary radiation means (10) for guiding and emitting radio waves at transmission, and guiding radio waves at reception, an antenna member (20) for reflecting radio waves emitted by the primary radiation means (10) and forming a transmission beam at transmission, and reflecting received waves on the primary radiation means (10) at reception, an angle adjustment means (40) for changing a relative angle between the primary radiation means (10) and the antenna member (20), an angle calculation means (81) for calculating the relative angle to be formed between the primary radiation means (10) and the antenna member (20) for displacement of an azimuth occurring in the primary radiation means (10), and a control means (82) for controlling the angle adjustment means based on the calculated relative angle.