An electromagnetic coupling device including a drive member coupled to the rotary shaft of an electric morot and a follower operating in response to the drive member. The drive member includes first and second magnet pole pieces and a magnetic path forming member. The drive member having a relatively large inertia, serves also as a flywheel. The follower is made to have a relatively small inertia to improve its response characteristic. The drive member has a space incorporating a fixed exciting coil and a fixed magnetic path forming member and a clearance accomodating eddy current generating plate thereby reducing the overall axial dimension of the electromagnetic coupling device.