Provided are an opposed iron core transmitting rotation motion, a manufacturing method thereof, and an electromagnetic fan clutch formed by the opposed iron core. The opposed iron core includes iron core grooves (12; 13) axially arranged in a back-to-back manner on an electromagnetic iron core body (11). The manufacturing method of the opposed iron core includes: directly drawing the iron core body (11) to form the iron core grooves arranged in the back-to-back manner, or directly spinning the iron core body (11) to form the iron core grooves arranged in the back-to-back manner. The electromagnetic fan clutch formed by the opposed iron core has a first actuation gap (841) and a second actuation gap (842) respectively on two sides of the electromagnetic iron core body (11) of an opposed iron core apparatus.