An electromechanical brake calliper , comprising a calliper body and an electromechanical actuator including: - a screw , rotatable about a longitudinal axis (x); - a nut screw , rotationally coupled to said screw , the nut screw being movable along a direction parallel to the longitudinal axis (x) of the screw ; - a movable thrust element , comprising its own longitudinal axis (y) and axially juxtaposed to the nut screw , onto which movable thrust element said nut screw engages; - a coupling interface between the nut screw and the movable thrust element , comprising at least a first coupling surface (C), obtained in the nut screw , and at least a second coupling surface (C', C IV ), obtained in the movable thrust element , said second surface (C', C IV ) being at least in part coupled to the first surface (C) and cooperating in a thrust relation with said first surface (C) ; wherein one (C) of said coupling surfaces (C, C', C IV ) is concave and the other (C', C IV ) of said surfaces is convex, and engages the concave coupling surface (C), the arrangement of said surfaces (C, C', C IV ) being such that it allows a relative oscillation of the nut screw with respect to the movable thrust element about a single predetermined axis (k), essentially transversal to the longitudinal axis (x) of the screw ; and wherein the relative rotation about the longitudinal axis (y) between the nut screw and the piston is hindered; said actuator being characterised in that : the first and the second coupling surfaces (C, C', C IV ) are portions of coaxial cylindrical surfaces, substantially complementary to one another, the nut screw and the movable thrust element being shaped so as to allow a relative oscillation thereof about the axis common to said first and second coupling surfaces (C, C', CIV). - a screw , rotatable about a longitudinal axis (x); - a nut screw , rotationally coupled to said screw , the nut screw being movable along a direction parallel to the longitudinal axis (x) of the screw ; - a movable thrust element , comprising its own longitudinal axis (y) and axially juxtaposed to the nut screw , onto which movable thrust element said nut screw engages; - a coupling interface between the nut screw and the movable thrust element , comprising at least a first coupling surface (C), obtained in the nut screw , and at least a second coupling surface (C', C IV ), obtained in the movable thrust element , said second surface (C', C IV ) being at least in part coupled to the first surface (C) and cooperating in a thrust relation with said first surface (C) ; wherein one (C) of said coupling surfaces (C, C', C IV ) is concave and the other (C', C IV ) of said surfaces is convex, and engages the concave coupling surface (C), the arrangement of said surfaces (C, C', C IV ) being such that it allows a relative oscillation of the nut screw with respect to the movable thrust element about a single predetermined axis (k), essentially transversal to the longitudinal axis (x) of the screw ; and wherein the relative rotation about the longitudinal axis (y) between the nut screw and the piston is hindered; said actuator being characterised in that : the first and the second coupling surfaces (C, C', C IV ) are portions of coaxial cylindrical surfaces, substantially complementary to one another, the nut screw and the movable thrust element being shaped so as to allow a relative oscillation thereof about the axis common to said first and second coupling surfaces (C, C', CIV). <EOS>