PURPOSE: To provide a method for regenerating a dummy block or a clean out disk of an extruding tool by which the dummy block or the clean out disk which is worn by use is reusable by regenerating.

CONSTITUTION: This method is a method for regenerating the dummy block or the clean out disk 11 which is attached at the tip of mandrel of the extruding tool and the outer peripheral end parts of flanges of the dummy block or the clean out disk 11 which is worn by use are cut into a ring-shape, rings 31, 32 whose outside diameter which is mated to the inside diameter of a liner are fit in the cut part and the flanges 21, 22 after cutting and the rings 31, 32 are welded by electron beam welding.