PURPOSE: To manufacture a sound precision casting by constituting it of specified wt.% of C, Cr, Ni, W, Ti, Al, Fe, B, Zr and either Ta or Nb and the balance Co.

CONSTITUTION: A high corrosion resistant cobalt base alloy is constituted of, by weight, 0.3 to O.7% C, 24.5 to 33% Cr, 8 to 12% Ni, 5 to 9% W, 0.2 to 0.5% Ti, 0.05 to 0.2% Al, ≤0.2% Fe, 0.005 to 0.015% B, ≤0.1% Zr, 3 to 4.5% of at least either Ta or Nb and the balance Co with inevitable impurities. In this way, the high corrosion resistant cobalt base alloy as the material constituting parts small in the fear of grain boundary oxidation at the time of parts manufacturing and combining sufficient oxidation resistance, corrosion resistance and creep resistance even at a high driving temp. can be offered.