The invention relates to an optical-electrical wiring board (2) and an optical module (1). The optical-electrical wiring board (2) includes a substrate (8), a dielectric layer (11), first conductive layers (16a) and second conductive layers (16b). The dielectric layer (11) includes a first region (B) and a second region (C). The first region (B) constitutes a plurality of light transmission portions (11B). The second region (C) has a plurality of pairs of conductive layers each having an overlap portion (10) in which one of the plurality of second conductive layers (16b) and one of the plurality of first conductive layers (16a) overlap each other when seen through in a laminated direction (a) of the dielectric layer (11) and the substrate (8).