The present invention provides a method of manufacturing a wiring board, including the steps of preparing a composite sheet having an adherent sheet containing a thermosetting resin adhered to a porous film or impregnated with at least a part thereof, laminating at least the composite sheet on a wiring layer having a wiring pattern formed on an insulating layer, and heating and pressurizing the laminated product thus obtained or heating and pressurizing it after the pressurization to integrate the laminated product.