Abstract: A wiring board according to the present disclosure includes a core insulating layer, a first laminated body located on an upper surface of the core insulating layer, and a second laminated body located on a lower surface of the core insulating layer. Each of the first laminated body and the second laminated body has a structure in which at least four electrical conductor layers and at least three build-up insulating layers are alternately located. The electrical conductor layers include two types, that are a first electrical conductor layer and a second electrical conductor layer. In the electrical conductor layers in the first laminated body, at least a first outermost layer and a first innermost layer are the first electrical conductor layers, and a first intermediate layer located farther from the core insulating layer than the first innermost layer includes at least two or more of the second electrical conductor layers.