Roll electrode for use in a seam welding machine

In a roll electrode for use in a seam welding machine comprising a stator member, a rotor member surrounding said stator member with an annular gap therebetween, a bearing member for rotatably supporting said rotor member to rotate about the axis of said stator member, and electrical conductive liquid filled in said annular gap for electrically connecting said rotor member to said stator member, the improvement wherein said electrical conductive liquid comprises a liquid metal consisting of 69.5.+-.5.0 atomic % of Ga, 15.2.+-.1.0 atomic % of In, 6.1.+-.1.0 atomic % of Sn, 4.5.+-.0.8 atomic % of Zn, 3.2.+-.0.5 atomic % of Ag and 1.5.+-.0.5 atomic % of Al, and wherein a substance comprising one or more of W, Mo, V, Ti, mixture thereof and alloys therefrom is secured to the lower portion of the outer surface of said stator member which defines said annular gap.