A reinforcing device for earthworks comprises at least one reinforcing base element (3) from which extend a front wall (9) and a containment wall (15) which are spaced from each other to delimit, in an operative configuration in which they are erected with respect to the reinforcing base element (3), a facing region which is to be filled with filling material, such as stones or the like. The device also comprises bracket means (23) which can be coupled, in use, to the front wall (9) and to the containment wall (15). It is also possible to produce a second front wall which extends from the reinforcing base element (3) on the side opposite the first. A method for the production of a reinforced earthwork provides for laying on the ground a device of the type indicated.