The temperature and concentration dependences of the dc electrical conductivity of glasses in the PbF₂-PbO · B₂O ₃ system are investigated. It is found that the dependences logσ = f([PbF₂]) and E_σ = [PbF₂]) for glasses containing ∼20 and ∼35 mol% PbF₂ exhibit kinks, which are interpreted from the standpoint of the microinhomogeneous structure associated with the selective interaction of the components during the synthesis of glasses. Analysis of the transport numbers has revealed that the unipolar fluorine ionic conductivity is observed upon introduction of more than 35 mol% PbF₂. It is shown that, in the concentration range from 0 to 35 mol% PbF₂, the electric current is provided by both protons and fluorine ions.