An antenna device includes a ground plane configured to have an end side; a ground element configured to have a first end and a second end; a first radiation element configured to have a first line extending upright with respect to the ground element from a grounded end, a second line coupled to the first line, and a feed point; a second radiation element configured to have a third line, and a fourth line coupled to the third line; a first parasitic element configured to have a first parasitic line, and a second parasitic line coupled to the first parasitic line and extending along the ground element toward the first end; and a second parasitic element configured to have a fifth line located close to a tip of the second parasitic line, and a sixth line extending along the ground element from a tip of the fifth line.