Abstract: A lead member includes a flat conductor having a top face and a bottom face, and insulation films 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 ?m, and smaller than, or equal to 5.0 ?m.