An electromechanical latch actuation device intended to be mounted on a face of a leaf equipped with a latch, the electromechanical latch actuation device comprising: - a coupling mechanism movable in rotation capable of being secured in rotation with a rotor of a latch cylinder of the latch, - an actuator comprising an electric motor and making it possible to electrically drive in rotation the coupling mechanism, - an operating button movable in rotation adapted for a manual grip and allowing the coupling mechanism to be manually driven in rotation, electromechanical latch actuation device in which the coupling mechanism comprises on the one hand a rotational drive part capable of being coupled in rotation in a reversible manner with a key inserted in the rotor of the latch cylinder and comprising first rotational coupling elements capable of cooperating with the key in a manner making the key and the rotational drive part secured in rotation about the axis of rotation of the rotational drive part, on the other hand a connecting part capable of constituting an intermediate adapter between the rotational drive part and a coupling member of the rotor of the latch cylinder projecting from the rotor of the latch cylinder, in which the connecting part is capable of being coupled in rotation in a reversible manner with the rotational drive part and comprises second rotational coupling elements capable of cooperating, when the connecting part is coupled with the rotational drive part, with the first rotational coupling elements to make the connecting part and the rotational drive part secured in rotation about the axis of rotation of the rotational drive part, in which the connecting part comprises third rotational coupling elements capable of cooperating with the coupling member of the rotor of the latch cylinder in a manner making the coupling member and the connecting part secured in rotation about the axis of rotation of the rotational drive part. - a coupling mechanism movable in rotation capable of being secured in rotation with a rotor of a latch cylinder of the latch, - an actuator comprising an electric motor and making it possible to electrically drive in rotation the coupling mechanism, - an operating button movable in rotation adapted for a manual grip and allowing the coupling mechanism to be manually driven in rotation, electromechanical latch actuation device in which the coupling mechanism comprises on the one hand a rotational drive part capable of being coupled in rotation in a reversible manner with a key inserted in the rotor of the latch cylinder and comprising first rotational coupling elements capable of cooperating with the key in a manner making the key and the rotational drive part secured in rotation about the axis of rotation of the rotational drive part, on the other hand a connecting part capable of constituting an intermediate adapter between the rotational drive part and a coupling member of the rotor of the latch cylinder projecting from the rotor of the latch cylinder, in which the connecting part is capable of being coupled in rotation in a reversible manner with the rotational drive part and comprises second rotational coupling elements capable of cooperating, when the connecting part is coupled with the rotational drive part, with the first rotational coupling elements to make the connecting part and the rotational drive part secured in rotation about the axis of rotation of the rotational drive part, in which the connecting part comprises third rotational coupling elements capable of cooperating with the coupling member of the rotor of the latch cylinder in a manner making the coupling member and the connecting part secured in rotation about the axis of rotation of the rotational drive part.