Platinum nanoclusters of average size 1.3 nm, modified with alkylamine, and alkylthiol, were prepared by a simple phase-transfer method using a small Pt nanocluster stabilized by glycol and OH- as a building block. Transmission electron microscopy, thermogravimetric analysis, H-1 NMR, and X-ray photoelectron spectroscopy analyses were carried out on these metal nanoclusters. It was observed that the Pt 4f binding energies in the same-sized Pt nanoclusters modified with alkylamine, alkylthiol, PVP, PVA, or PPh3 increase by 0.5-0.8 eV relative to those of bulk Pt. The shifts in the binding energies are caused by a size effect of the small Pt core and a ligand effect from the modifiers. By deducing the small size effect, the ligand effect on the Pt 4f binding energies was studied.