It is possible to provide a multi-layer wiring board which can be contained in a case of an electronic device with a high density. A multi-layer wiring board (12) has a structure formed by a printed circuit board (6) having no flexibility layered via a cover lay (10) on both sides of a printed circuit board (1) having a flexibility. In the multi-layer wiring board (12), the cover lay (10) protects a portion of the printed circuit board (1) where the printed circuit board (6) is nor present and functions as an adhesive layer (11) for bonding the printed circuit board (6). That is, in the multi-layer wiring board (12), the cover layer (10) and the adhesive layer (11) are the same layer.