PbTe single crystals were prepared by the Bridgman method, where either Ag₂Te or PbI₂ was doped as the source material of silver or iodine. The hole concentration was successfully controlled in the range from 2.0×10²⁴ to 9.0×10²⁴ m⁻³ by doping 100 to 700 mol ppm Ag₂Te, and then the conduction type changed at 1000 mol ppm. By doping 100 to 650 mol ppm PbI₂, the hole concentration decreased from 4.5×10²⁴ to 3.5×10²³ m⁻³. The conduction type changed from p- to n-type in the region of more than 700 mol ppm PbI₂, where electron concentration was controlled in the range from 5.0×10²² to 5.0×10²⁵ m⁻³ by doping 700 to 6000 mol ppm. Scattering factor (r) was estimated for both p- and n-type PbTe from the temperature dependence of Hall mobility in the range of 77 to 300 K. Thermal conductivity (κ) at 300 K was calculated in terms of the carrier concentration by evaluating the lattice (κ_ph) and electronic (κ_el) components. The κ_el was estimated on the basis of Fermi integral by using observed data on thermoelectric power (α) and r, while the κ_ph was estimated to be 2.15 Wm⁻¹K⁻¹ using calculated κ_el value and the observed κ data for undoped PbTe. Maximum figures of merits (Z_max) of PbTe at 300 K were 1.21×10⁻³ K⁻¹ for the n-type at n=2.76×10²⁴ m⁻³ (2000 mol ppm PbI₂) and 1.38×10⁻³ K⁻¹ for p-type at p=2.34×10²⁴ m⁻³ (200 mol ppm Ag₂Te).