A propulsion device for a vehicle, in particular a watercraft, comprising: - at least one shaft extending along a longitudinal axis, and rotatable around the longitudinal axis, - a support for said shaft, intended to be secured to the vehicle, including means for guiding the rotation of the shaft around the longitudinal axis, - at least one propeller with swiveling blades, including: • a propeller hub coaxial to said shaft and secured to this shaft in rotation around the longitudinal axis, and • at least one blade, secured to the propeller hub in rotation around the longitudinal axis, and rotatable relative to the propeller hub around a radial axis perpendicular to the longitudinal axis, - means for moving said plate in rotation around said radial axis, characterized in that the movement means comprise: - an electric motor, including a case and a stator that are secured to said support, and a rotor arranged across from the stator, rotatable around the shaft, said stator being supplied with energy through said support, - a slide with a general shape of revolution around the longitudinal axis, - kinematic connection means between the rotor and the slide, able to convert a rotation of the rotor around the longitudinal axis into a translation of the slide parallel to the longitudinal axis, and - connecting means connecting the slide with each blade, able to convert a translation of the slide parallel to the longitudinal axis into a rotation of each blade around the corresponding radial axis. - at least one shaft extending along a longitudinal axis, and rotatable around the longitudinal axis, - a support for said shaft, intended to be secured to the vehicle, including means for guiding the rotation of the shaft around the longitudinal axis, - at least one propeller with swiveling blades, including: • a propeller hub coaxial to said shaft and secured to this shaft in rotation around the longitudinal axis, and • at least one blade, secured to the propeller hub in rotation around the longitudinal axis, and rotatable relative to the propeller hub around a radial axis perpendicular to the longitudinal axis, • a propeller hub coaxial to said shaft and secured to this shaft in rotation around the longitudinal axis, and • at least one blade, secured to the propeller hub in rotation around the longitudinal axis, and rotatable relative to the propeller hub around a radial axis perpendicular to the longitudinal axis, - means for moving said plate in rotation around said radial axis, characterized in that the movement means comprise: - an electric motor, including a case and a stator that are secured to said support, and a rotor arranged across from the stator, rotatable around the shaft, said stator being supplied with energy through said support, - a slide with a general shape of revolution around the longitudinal axis, - kinematic connection means between the rotor and the slide, able to convert a rotation of the rotor around the longitudinal axis into a translation of the slide parallel to the longitudinal axis, and - connecting means connecting the slide with each blade, able to convert a translation of the slide parallel to the longitudinal axis into a rotation of each blade around the corresponding radial axis.