Dielectric measurements are performed for nonstoichiometric single crystals of lead germanate and the temperature dependences of dielectric permittivity along the ferroelectric axis are studied in the temperature range 315–530 K. Basing on statistical processing of the experimental data, we show that the critical behavior of the crystal due to ferroelectric phase transition is satisfactorily described by the Curie–Weiss law corrected by a temperature-dependent dielectric background.