There is provided a method of stably producing nanoparticles of a metal alone, in particular a transition metal alone, the method comprises heating a chelate complex (M-DMG) comprised of two dimethyl glyoxime (DMG) molecules and one transition metal (M) ion at 300 to 400° C. so as to generate transition metal (M) nanoparticles carried on carbon particles. The method preferably comprises heating a mixture of said chelate complex (M-DMG) and alumina so as to generate transition metal (M) nanoparticles carried on alumina. Preferably, the transition metal (M) is one of Ni, Cu, Pd, and Pt. Typically, the generated transition metal (M) nanoparticles have a size of a diameter of 5 to 15 nm.