PURPOSE: To decrease the man-hours for removing resin and reduce generation of such defects in a porous W-rod as cracking chipping, etc., by machining away the resin attached to the side of the porous W-rod using a lathe.

CONSTITUTION: W powder is solidified by a hydraulic press and sintered so as to assume a columnar form. At the top and bottom surfaces of this column, cylindrical recesses 3 are formed using a drill in the same direction as the axis of the column. This work is subjected to resintering in a reductive atmosphere to obtain a porous W-rod 1. Under a vacuum, this W-rod 1 is impregnated with a resin 2 of methyl acrylate monomer, etc., which is then heated and solidified. The resin 2 in the recesses 3 is removed using drill, and upon setting on a lathe the resin attached to the side of the W-rod 1 is machined off by a cutting tool, and thus a base body for impregnated cathode is produced. This base body is further impregnated with Ba oxide, Ca oxide, and Al oxide, and thus a high quality cathode of impregnated type is accomplished. Besides cylindrical, the recess 3 may assume symmetrical about the axis, polygonally pyramidal, or polygonally columnar.