The invention provides a method for inexpensively and stably manufacturing a multilayer wiring board having a cable section with a high integration degree capable of loading narrow
pitch CSP. The manufacturing method of the multilayer flexible wiring board having the cable section in at least an outer layer, includes a) a process for manufacturing an inner layer core substrate (8, 58); b) a process for forming an opening of
copper foil in a conduction hole forming part on an outer layer side in a double sided
copper clad laminate having flexibility, and forming a circuit pattern (10, 60) comprising an opening of a conduction hole forming part on an inner layer side of the double sided
copper clad laminate; c) a process for forming a cover
ray (22, 70) on the circuit pattern to make it to be an outer layer built-up layer (23, 67); d) a process for laminating the outer layer built-up layer by turning a side where the cover
ray is formed to a side of the inner layer core substrate, and forming the lamination circuit substrate (25, 73); e) a process for performing
laser processing on the conduction hole forming part of the outer layer side through the opening of
copper foil, and forming a conduction hole (26, 27, 28, 74, 75, 76) in the lamination circuit substrate; f) a process for performing
laser processing on the conduction hole forming part of the outer layer side by acting the opening of the
copper foil and the opening of the conduction hole forming part as a
mask for shielding
laser, and forming the conduction hole in the lamination circuit substrate; and g) a process for performing a conduction
processing on the conduction hole, and forming a via hole (29, 30, 31, 77, 78, 79) with electrolytic plating. The double sided copper clad laminate can be replaced by a single sided copper clad laminate.