A rotary actuator with a moving frame includes an electrical coil that moves on an angular travel about an axis of rotation A, the shape of the coil being an elliptical cylinder and the axis of winding B being orthogonal to the axis of rotation A, the coil being placed in the magnetic field of a fixed magnet. The fixed magnet surrounds the coil and includes two semicylindrical portions, the generatrices of which are orthogonal to the axis of rotation A, the first of the semicylindrical portions having a north pole directed toward the coil, orthogonally to the direction of the generatrices and being positioned outside the coil, the second having a south pole directed toward the coil, orthogonally to the direction of the generatrices and also being positioned outside the coil opposite the first portion. The actuator includes a ferromagnetic core inside the coil and an outer ferromagnetic yoke surrounding the fixed magnet, the coil moving in the air gap formed between the magnetized semicylindrical portions and the inner core.