The quantum yields eta of internal photoemission on a Au/GeO2/Ge layered system was measured for various bias voltages. From the photon energy dependences of eta for positive and negative biases, the barrier height at GeO2/Ge and Au/GeO2 interfaces was determined to be 2.08 eV and 1.93 eV, respectively. On the basis of these results, the band diagram at flat band conditions was constructed and some discussions were made on the mechanisms of photoconduction for GeO2/Ge films.