In an antenna device, a first coil conductor portion of a coil conductor faces a planar conductor to at least partially overlap with the planar conductor when viewed in a plan view. A second coil conductor portion of the coil conductor does not overlap with the planar conductor when the planar conductor is viewed in the plan view. On a straight line passing a center of gravity of a coil opening of the coil conductor when the planar conductor is viewed in the plan view, a first distance between the first coil conductor portion and a first edge is shorter than a second distance between the first coil conductor portion and a second edge. The second distance is shorter than a third distance between the center of gravity of the coil opening and a second edge on the straight line passing the center of gravity of the coil opening.