To enhance adhesion between a wiring and an insulation layer by removing a sheet-like metallic material through etching while leaving a thin conductive film on one side of an insulation layer, forming a metal wiring on the thin conductive film on one side of an insulation layer and then removing the thin conductive film through etching except a region for forming the metal wiring.

A thin conductive film 120 is provided on the roughened surface side 110S of a sheet-like metallic material 110 and an insulation layer 130 of organic polymer is provided by casting on the thin conductive film 120. The thin conductive film 120 on one side of the insulation layer 130 is then coated with a plating resist 150 for forming a metal wiring 160 and processed and a metal wiring 160 is formed on the thin conductive film 120 by copper plating. Subsequently, the plating resist 150 is stripped and the thin conductive film 120 is removed by etching to produce a flexible printed wiring board 180. According to the arrangement, adhesion between the metal wiring 160 and the insulation layer 130 is enhanced and a fine pattern wiring can be formed.