A modified metal complex obtained by subjecting a metal complex containing an organic compound having one nitrogen-containing aromatic heterocycle and four or more structures of a phenol, thiophenol, aniline or nitrogen-containing aromatic heterocyclic ring or an organic compound having two or more phenol rings and three or more nitrogen-containing aromatic heterocycles, in its molecule as a ligand, to a heating, radiation irradiation or discharge treatment until a mass reduction rate after the treatment becomes from 1 to 90 mass %, thereby the complex shows a carbon content after the treatment of 5 mass % or more.