A transfer sheet for use in forming a conductor circuit comprises a base and a metal layer formed into a circuit pattern on the base. The metal layer is transferred onto a surface of an insulation layer. At least part of the circuit pattern of the metal layer is formed by laser-processing. Since it is possible, without using an etching process and a plating process at a minute part of the conductor circuit, to remove the metal layer by emitting laser light having a minute beam diameter, it is possible to form a minute conductor circuit which is 50 m or less in width and pitch, with the result that it is prevented that the conductor circuit has a break because of excessive etching and a failure of plating deposition or the conductor circuit is short-circuited because of the residue of etching and a short of plating.