An antenna device 1 has a capacitive coupling element 10 mounted on a printed circuit board 20. Strip patterns 21 to 23 are provided in a grand clearance region 20A defined on one principal surface of the printed circuit board 20. The strip pattern 21 is connected to a feeding line 29 after extending in a first direction from the connecting point with the capacitive coupling element 10. The strip pattern 22 is connected to a feeding line 30 after extending in a second direction, that is an opposite to the first direction, from the connecting point. The strip pattern 23 is connected to a ground pattern 24 after extending in a third direction from the connecting point. The capacitive coupling element 10 is disposed with an offset toward the first direction. The strip pattern 21 is shorter in length than the strip pattern 22.