An electromagnetic clutch includes a rotor, armature hub, armature, magnetic body and first permanent magnet, field core, excitation coil, and second permanent magnet. The rotor is rotatably disposed in the housing of a driven device. The armature hub is fixed to the rotating shaft of the driven device. The armature is disposed on the armature hub to be movable in an axial direction. The magnetic body is incorporated in the rotor. The first permanent magnet connects the armature to the rotor. The field core is attached to the housing and inserted in the rotor to be in noncontact with it. The excitation coil is disposed in the field core and excited, when cutting off power transmission, to cancel a magnetic force of the first permanent magnet, thus releasing the armature from the first permanent magnet. The second permanent magnet separates the armature from the rotor, when cutting off power transmission, to move the armature toward the armature hub. The first permanent magnet has a Curie temperature lower than the temperature of heat generated by the rotor upon slip rotation.