To eliminate the need of welding and speed up repairing work when a furnace bottom electrode of a DC electric furnace is repaired by cooling a portion to be repaired and then disposing a construction frame so as to surround the furnace bottom electrode, and putting a conductive stamp material in the construction frame and lap piling them, and then applying a usual stamp material.

When a furnace bottom electrode is repaired, in which electrode positive electrode pins 1... protected by a trapezoidal refractory of a DC electric furnace are fixed to a pin mount plate 3 through a substrate 2, after the portion to be repaired is cooled between predetermined temperatures, an iron plate is rounded matched with the original size of a furnace bottom electrode block to form a ring-shaped construction frame 21. The construction frame 21 is lifted with a lifting tool, and is set so as to surround the upper part of the worn furnace bottom electrode up to a broken line A. Then, a proper amount of a conductive stamp material 20 is inserted into the construction work 21 and is stamped with an air hammer, and is filled between the original electrode thicknesses. Thereafter, a general stamp material is filled up to the thickness of the furnace bottom on the outside of the construction frame with a conventional method for completion of the repair.