An electromechanical actuator includes a spring brake with a helical spring, a drum, an input member, an output member and a cap. The drum includes a housing with an inner friction surface configured to cooperate with at least one turn of the spring. The input member includes a driving tooth extending between the input member and the cap. The input member or the cap includes a spacer extending between the input member and the cap. The input member includes a first radial retention element of the spring extending between the tooth and the spacer, along a first side of the brake. Furthermore, the cap includes a second radial retention element of the spring extending between the tooth and the spacer, along a second side of the brake.