Abstract: An electromagnetic clutch includes a first rotatable member rotatably supported on a first bearing. The first rotatable member is provided with at least one annular groove along an outer surface thereof for receiving a belt rotatably connecting the first rotatable member to an external driving source. The first rotatable member further has an inner and outer cylindrical annular portions and a magnetic axial end plate connecting the cylindrical annular portions at an axial one end. The magnetic axial end plate has a plurality of arcuate slits disposed on at least one circle. A plurality of remaining regions are located between each pair of adjacent slits. A second rotatable member is rotatably supported on a second bearing. An annular magnetic member is supported on the second rotatable member so as to be capable of limited axial movement. The annular magnetic member faces the axial end plate of the first rotatable member with an axial gap therebetween.