In an electrode for a spark plug, an elongated blank metal is made of a nickel-based alloy and including a front surface. A firing tip is provided from a slug made of a noble metal, the slug being concentrically placed on the front surface of the elongated blank metal and laser beam welded to thermally melt the entire slug and thereby produce a thermal weld, so that the front surface of the elongated blank metal is partly fused together with the slug to form a melted portion with the front surface and the slug so as to contain the front surface within the melted portion in the range of 0.5 wt % to 80.0 wt %.