An electromagnetic device includes a spool having a cylindrical body with a through hole, a secondary coil formed in a spiral shape along an outer peripheral surface of the cylindrical body and formed with a closed circuit by metal plating, and a primary coil formed of a conductive wire wound around the secondary coil via an insulating material covering the secondary coil. An induced current, generated by applying a voltage to any one of the primary coil and the secondary coil, is allowed to flow to the other coil different from the one coil.