To shorten the dimension in the axial direction of an electromagnetic coupling device provided with an electromagnetic clutch and an electromagnetic brake, and to prevent vibration of an armature when the electromagnetic clutch and the electromagnetic brake are de-energized.

A hub 13 made of non-magnetic material and having a stopper portion 13a formed on the peripheral surface is mounted on a driven shaft 12. An armature 9 for the clutch fitted in a spline groove 13b of the hub 13 and an armature 14 for the brake fitted in a cylinder portion 13c of the hub 13 are coupled by means of a plate spring 19 made of non-magnetic material. The counter-friction surface of the armature 9 for the clutch and the counter- friction surface of the armature 14 for the brake are constituted to abut on the stopper portion 13a of the hub 13 due to the initial elasticity recovery force of the plate spring 19.