Behavior of silicon (Si) and germanium (Ge) atoms (or clusters) on the surface of a C-60 fullerene has been revealed by using time-of-flight mass spectroscopy and photoelectron spectroscopy. The mixed clusters of C(60)Sin and C60Gem were generated by two-lasers vaporization of a molded C-60 rod and a Si (or a Ge) rod in He carrier gas. The size distributions of anionic and cationic C60Sin/C60Gem clusters monotonically decreased with the number of Si/Ge atoms, and were limited only up to n = 4 and m = 3. The photoelectron spectra of C60Sin- and C60Gem- are similar to that of pure C-60(-) at n, m = 3, 4, whereas the spectra at n, m = 1, 2 are different from that of C-60. These results show that Si/Ge atoms assemble together into Si/Ge clusters on the C-60 cage with an increase in the number of Si/Ge atoms.