We studied the electrical properties of thermally treated V2O5-CuO-Fe2O3-P2O5 (vanadate) glasses under reducing high-vacuum conditions. The glasses were prepared by using a melt-quenching method and then applied on Al2O3 substrates as ∼40μm-thick films. The glass films were then heat treated at 375−550°C under a vacuum of 10−6 Pa. Powder X-ray diffraction showed the formation of complex oxides of both MxV2O5 (M = Cu, Fe; x = 0.12−1.3) and vanadium oxides (VOx; x = 1.5−2.5). The resistivity of the glass film crystallized at 550°C measured at 50°C and 300°C were 1.8 × 100 Ωcm and 2.8 × 10−1 Ωcm, respectively, which was 10 times lower than that of the film crystallized in air. The Seebeck coefficient was −132 μV/K at 50°C and −130 μV/K at 300°C. These results show that the vanadate glasses crystallized under the appropriate condition become potential candidate materials for semiconductor and thermoelectric application.