A propulsion device for a rotating blade aerodyne with vertical take-off and landing, comprising a hollow chassis and contra-rotating coaxial rotors with fixed-pitch blades. The means for driving the rotation of each rotor comprise motor means and, for each rotor, a rotating part capable of turning about a yaw axis, located in the central opening of the respective rotor and connected to the latter via a ball joint with finger, the centre of which is the intersection of the prospective rotor disc and the yaw axis and for which the prohibited rotation is that about the axis of rotation of the rotor. Means for controlling the inclination of the rotors about the roll and pitch axes. Aerodyne equipped with the propulsion device.