A wiring board capable of suppressing migration between wires and to provide a method of producing the same, in a method of producing a wiring board provided with a first wiring board in which a first wiring layer is formed, and a second wiring board in which a second wiring layer finer than the first wiring layer is formed, the second wiring board is formed by performing steps of forming a first insulating resin layer provided with a wiring pattern and openings, forming a first inorganic insulating film on the first insulating resin layer, forming a first conductor layer corresponding to the wiring pattern and the openings on the inorganic insulating film, and forming a second inorganic insulating film on the first conductor layer.