PURPOSE: To obtain a build-up roll excellent in resistance to wear and heat, and surface roughening, by build-up welding specific powder to the roll surface by plasma welding.

CONSTITUTION: By connecting a water-cooled copper electrode 2 to the posi- tive side of an electrode 6 and a base metal 1 to its negative side, and by feeding a plasma gas 7 from a passage 3, a moving type plasma-arc column 8 held in the plasma gas is generated between the electrode 2 and the metal 1. At the same time, powder 10 containing 20W60vol% carbide metal and the balance consisting practically of Co or Co-base alloy powder, is fed by a carrier gas 9 to an arc of column 8 to melt-stick the powder 10 to the material 1, thereby obtaining a desired build-up welded metal 11. Further, a shield gas 12 is simultaneously fed from a passage 5 to the surroundings of the welded part, to protect the molten pool.