An antenna structure according to an embodiment of the present disclosure includes an antenna unit array including a plurality of antenna units, and a parasitic element disposed to be adjacent to the antenna units and to be electrically and physically separated from the antenna units. Each of the antenna units includes a radiator, and a transmission line including a first transmission line and a second transmission line connected to the radiator in different directions. The parasitic element includes a first parasitic element disposed between the first transmission line and the second transmission line included in the same antenna unit, and a second parasitic element disposed between the first transmission line and the second transmission line included in different neighboring antenna units. The second parasitic element includes a branched portion including a first branched portion and a second branched portion bent in different directions.