PURPOSE: To provide the titanium base alloy with excellent corrosion resistance and coercive corrosion resistance and to improve its strength at cold and high temps. by adding specified amounts of Al, Ni and Pb to Ti and regulating the content of oxygen.

CONSTITUTION: The compsn. of the Ti base alloy is formed of, by weight, 1 to 4% Aq, ≤0.25% O, ≤ 0.3% Fe, 0.4 to 1.6% Ni and the balance Ti with inevitable impurities. Or, instead of Ni, 0.01 to 0.25% Pb is incorporated thereto. Furthermore, in the case of composite addition of Ni and Pb, the amt. of Ni to be added is regulated to ≤1.6% and Pb to ≤0.25% as well as the ratio of 1/40Ni(%)+Pb(%) is regulated to ≥0.01%. The Ti alloy can be used as the members for chemical plants and various apparatus requiring high strength and high corrosion resistance.