The invention relates to an electromechanical actuator comprising a frame (1) and an electric motor (2) driving at least one movement transmission element (3) connected to the frame by means of a braking device (6) and a unidirectional transmission member (4). The braking device comprises an electric activation member (6.6) such that, when power is being supplied to the activation member, the unidirectional transmission member is disconnected from the frame and, when power is not being supplied to the activation member, the unidirectional transmission member is solidly connected to the frame and opposes the pivoting movement of the transmission element in a direction of rotation up to a maximum transmissible torque defined by the braking device.