Three kinds of peroxo-polytungstic acid (PPTA, C-PPTA and N-PPTA) were obtained by reacting hydrogen peroxide with metallic tungsten, tungsten carbide or tungsten nitride, respectively, Polytungstates, C-PPTA and N-PPTA, were found to contain oxalate and nitrate ligands. Their proton conductivities were compared using thin film specimens spin-coated from their water solution. Conductivity of each as-coated him was in the range from 10(-3) to 10(-4) S cm(-1) under the relative humidity of 40% (25 degrees C). A sharp decrease in conductivity (to less than 10(-7) S cm(-1) at 25 degrees C) was observed for PPTA without acidic ligands after thermal treatment at 80 degrees C. However, the effect of thermal treatment on C-PPTA or N-PPTA was much milder. A 80 degrees C-treated C-PPTA film showed the conductivity of 1.0 x 10(-5) S cm(-1) (25 degrees C) with a very weak dependency on ambient humidity.