A non-rotary electrode for forming holes in metal workpieces by electro-erosion in which the through bore of passage for the dielectric fluid is spiral and generates a substantially crescent-shaped area when a cross-section is taken through the entire electrode, the maximum transverse depth of the crescentshaped area extending up to the central axis of the electrode as a maximum so that substantially no build-up of a central plug in the workpiece occurs due to trepanning as the active end of the electrode is consumed in the process. The invention also includes electro-erosion apparatus and an electro-erosion method using the non-trepanning, non-rotary electrode.