An antenna device has: an antenna coil inductively coupled to the external device and provided by winding around a conducting wire such that wires opposing in width direction via an opening will be close to each other and divided such that one side part in which the wire is wound around in one direction and other side part in which the wire is wound around in other direction, via a center line longitudinally traversing the opening in a longitudinal direction; and an electronic apparatus cover having an opening, wherein the cover is having a magnetic shielding function, and the antenna coil is arranged in the opening provided at the cover such that the antenna coil is not overlapped with the cover, and also, an area of the cover opening at the other side part side is wider than an area of the cover opening at the one side part side.