An electromagnetic coupling apparatus includes an armature hub, a leaf spring, an armature, a rubber stopper, a fixing member, a rubber vibration insulator, a rotor, an electromagnetic coil, and a field core. The armature hub is fixed to the rotating shaft of a unit and has a flange portion formed with a through hole. The fixing member is fixed to the armature and has a trunk portion and a head portion formed with an annular wall portion on its outer circumference. The rubber vibration insulator is disposed between a side surface of the flange portion of the armature hub and the head portion of the fixing member, and is constituted by a cylindrical portion and a disk portion. The rotor opposes the armature through a first gap of a predetermined size. A second gap larger than the first gap is formed between a distal end of the wall portion of the fixing member and the flange portion of the armature hub, and a third gap is formed between one side surface of the disk portion of the rubber vibration insulator and the side surface of the flange portion of the armature hub.