Abstract: An electromagnetic braking device for braking a rotary shaft includes a friction disk mounted to the shaft and movable in translation and rotation, an outer part, and an intermediate part movable in translation between the friction disk and the outer part. At least one of the outer and intermediate parts is magnetic. At least one electromagnetic actuating member and at least one mechanical actuating member are housed in the other of the outer and intermediate parts. The intermediate part moves in a first direction toward the friction disk under the action of the mechanical actuating member and in a second direction toward the outer part under the action of the electromagnetic actuating member. A plurality of independent magnetic sheets move in translation between the intermediate and outer parts under the action of the mechanical actuating member and/or electromagnetic actuating member.