Electrochemical cells in the form of pressed pellets and polycrystalline films prepared from the PbSe + PbSeO₃ two-phase composite are investigated by impedance spectroscopy. The dispersion analysis of the frequencies of the real and imaginary parts of the complex impedance made it possible to reveal a unified equivalent electric circuit for these cells and to calculate its parameters. The optical (ε_hf) and static (ε_lf) permittivities of the PbSe and PbSeO₃ phases are determined. The permittivities ε_hf = 20-45 and ε_lf = 200-280 obtained for the PbSe phase are in reasonable agreement with the data available in the literature. The temperature dependences of the ac and dc resistances indicate that the PbSe + PbSeO₃ composite undergoes a phase transition at a temperature T _c ≅ 363 K.