The present invention provides a lead member, which is formed through plating nickel on copper, thereby enabling the connection intensity between metal foils made of nickel and not generating cracks on plating layers even if the metal foils are bended. Insulation films are adhered onto both faces of the conductor at a middle portion of the conductor along a length direction of the conductor. The conductor includes a base material that is copper and a nickel plated layer on the base material. A thickness of the conductor has a value larger than, or equal to 0.05 mm, and smaller than, or equal to 0.2 mm. A width of the conductor has a value larger than, or equal to 2 mm, and smaller than, or equal to 7 mm. A thickness of the nickel plated layer has a value larger than, or equal to 2.5 [mu]m, and smaller than, or equal to 5.0 [mu]m.