Provided are an antenna device and an electronic device in which a case is miniaturized and communication is stabilized by effectively using the magnetic shielding effect of a metal plate irrespective of the internal structure of a mobile device or the relation with other components. An antenna coil (12) is provided on an edge of an opening (111) provided in a cover (110) having the function of magnetically shielding the electronic device, the antenna coil (12) being disposed on an inner wall of the cover (110).