To provide a lead wire for an electronic part, which contains no poisonous lead although it has a plated film mainly containing Sn, is inexpensive, and can surely prevent the generation of whisker; and a flat cable comprising the same.

The lead wire is constituted of an electroconductive base body 1, a plated layer 2 of a Sn-alloy of Sn and Bi, Cu, Ag or Zn, which covers the surface of the base body 1, and an upper plated layer 3 of Zn, Ag, a SnZn alloy, a SnAg alloy or a SnBi alloy, which is formed on the plated layer 2. The content of Bi, Cu, Ag or Zn is set to be 0.1-15 wt.% and the total thickness of the plated layer 2 of the Sn-alloy and the upper plated layer 3 is designed to be 0.5-20 μm.