Pt nano-particle-attached carbon black particles (Pt/C) are synthesized by an arc plasma deposition (APD) process to improve electrocatalyst properties for polymer electrolyte membrane fuel cell applications. Thanks to the fine Pt particle size and high Pt particle number density by high resolution- transmission electron spectroscopy image analysis, the electrochemical active surface area of the catalyst is higher than a commercial Pt/C. However, Pt/C particles synthesized by APD process show limitations in Pt content and long-term stability in cyclic voltammetry experiments. Therefore, carbon black supporting Pt particles are modified by depositing indium-tin oxide (ITO) nano-particles by APD technique. Pt-ITO/C electrocatalysts formed by the APD process show high electrochemical performance with enhanced durability due to inertness of conductive metal oxides in oxidative conditions.