It is an object, with regard to a configuration for forming a macromolecular layer on a surface of a base material of an artificial joint composite, to achieve a size reduction, to accurately control ultraviolet irradiation intensity, to form a macromolecular layer having a uniform thickness, to suppress the influence of ultraviolet light on equipment and workers, and to make the occurrence of a malfunction unlikely. A film-producing device body (20) forms a macromolecular layer (12) in an inner surface (11e) of a base material (11) of an artificial joint composite, by means of photograft polymerization. The film-producing device body (20) includes a plurality of ultraviolet LED elements (60) and a work holder (24). On the work holder (24), solution (23) containing macromolecular monomers is in contact with the inner surface (11e) of the base material (11). The ultraviolet LED elements (60) emit ultraviolet light to a wider area than an area that each of the ultraviolet LED elements (60) individually irradiates.
