A manufacturing process of three-dimensional leather objects, including the following steps: applying a hardener additive on the flesh side of a piece of leather, positioning the flesh side of the piece of leather on a shape, introducing the shape with the piece of leather in a vacuum sack, applying rough vacuum in the vacuum sack, heating the vacuum sack with the shape and the piece of leather, and progressively applying vacuum during the heating step, stopping the vacuum pressure and cooling the vacuum sack with the shape and the piece of leather, opening the sack and extracting the shape with the piece of leather from the vacuum sack and removing the piece of leather from the shape in such a way that the piece of leather has the shape of a three-dimensional object.