Abstract: Provided is a method of manufacturing a multi-layered flexible print circuit board (FPC), which is capable of preventing an adhesive member of the multi-layered FPC from being peeled from FPCs. The invention provides a method of manufacturing a multi-layered flexible printed circuit board (multi-layered FPC) including laminating at least two flexible printed circuit boards laminated, wherein a side comprising a conductor circuit in which a conductor circuit of at least one of the at least two flexible printed circuit boards before being laminated is present is subject to an alkaline solution with a concentration of 0.2 to 6.0 wt % and a temperature of 20 to 45° C. under a treatment time of 20 to 100 seconds before the laminating.

Abstract: Provided are methods of manufacturing a flexible printed circuit board having a surface layer portion where a copper foil circuit is disposed and consisting single-side board, double-side board and multi-layer board. A first manufacturing method in a case when a single-sided CCL is used includes at least a step in which the surface layer portion is subjected to alkaline treatment, and a step to dispose a resist onto the alkaline-treated surface layer portion.