To enable the manufacture of a highly reliable injection-molded printed circuit body with the use of a flexible sheet which is outstandingly adhesive with a base material resin of the moldings by treating the surface of a plastic film layer by irradiation with ultraviolet rays before forming an adhesive layer on the plastic film layer.

A sheet 10 is made up of a metal layer 3 laminated on plastic film 2. Further, an etching resist layer 4 is formed by screen printing on the metal layer 3 in accordance with a circuit pattern. In addition, the unnecessary metal layer 3 is removed by etching process with a solution of copper chloride and then the etching resist is removed to form a metal circuit layer 5 on the film 2. An insulating layer 6 is perforated on the part where a circuit is exposed, and is laminated to the surface of the plastic film 2, after applying an adhesive layer to the plastic film 2. Next, the face, with which a base material resin comes into contact, of a flexible sheet is irradiated with untraviolet rays. Finally, an adhesive layer 7 is formed on the face irradiated with ultraviolet rays with the help of a roll coater.