Abstract: An apparatus for extending the arm of a lever, particularly for extending the arm of a lever of strap tensioning devices, comprising an element for connection to the lever, which can be associated therewith jointly and reversibly, a main body, which is associated with the connecting element by way of elements for mutual inclination and can be gripped by the user to operate the lever, and elements for contrasting the mutual inclination of the main body with respect to the connecting element, which can yield to a predefined force that contrasts the rotation of the lever, applied thereby to the connecting element.