High effectiv and sufficiently firm materials on the basis of the Bi85Sb15 solid solution doped by Pb impurites have been obtained and investigated. It is shown, that with growth of a doping degree values of thermoelectrical figure of merit (Z) at first grows up to 0,005 at. % Pb of and at this concentration reaches value equal ~5,0·10^–3 K^–1 at ~200 K, and then decreases. In a magnetic field the greatest values of Z for the samples of p-type has one doped by 0,05 at. of % Pb, and Z reaches value ~0,84·10^–3 K^–1 at ~80 K.