Abstract: Electrodes for use in spot welding which can spot-weld a metallic material having a large electric conductivity and a large thermal conductivity with a small electric current. A cup-shaped cap made of material having a small electric conductivity, a small thermal conductivity and a high melting point temperature as compared to the material to be welded, for instance, made of titanium, is fitted arond a tip end portion of an electrode main body. The top surface of the cap is formed in a spherical shape having a large radius of curvature, and a depression is formed at the central portion of the top surface. The thickness of the top wall is thick at the central portion and thin at the peripheral portion. Plating of soft metal having a better thermal conductivity than the electrode main body is applied onto the entire inner surface of the cap coming into contact with the electrode main body.