Affords efficiently and at low cost practical, tiny light-emitting devices having an optically diffractive film on their light-output face. A light-emitting device (LD) includes a diffractive film (DF) formed on its light-output face; the diffractive film includes a transparent DLC (diamond-like carbon) layer; and the DLC layer includes a modulated-refractive-index diffraction grating containing local regions of relatively high refractive index and local regions of relatively low refractive index.