Abstract: A refractory is laid on a base plate provided with a connector for the connection of a power source apparatus. Many electrode pins are inserted through the refractory and fixed in the base plate at their lower ends. The base plate is made of a steel upper plate member and a copper lower plate member overlapped one on the other and the lower end portions of the many electrode pins are electrically connected to the lower plate member through the upper plate member. When a DC electric arc furnace is operated, the electric current supplied to the connector reaches all the electrode pins mainly through the lower plate member in the base plate and flows from there homogeneously through the pins into the molten metal pool in the furnace.