A method for manufacturing an Ni base alloy pipe stock comprises piercing and rolling a billet by use of Mannesmann piercing and rolling mill. The pipe stock has controlled amounts of C, Si, Mn, P, S, Cr, Ni, Mo, W, Cu, Al, N, with the balance being Fe. With the method, the following equations are satisfied, wherein values of TGBm, Psr and Pσ represented by the following equations (1) to (3) being not more than 1300, not more than 200 and not less than 0, respectively TGBm=1380−5000P−100S−4400C  (1), PsrNi+10(Mo+0.5W)+100N  (2), Pσ=(Ni−50)+10(N−0.1)−2(Cr−25)−5(Mo+0.5W−6)+12  (3), wherein each element symbol in the equations represents mass % of the element concerned.