A wiring board includes: a first insulating layer; a second insulating layer that is formed on an upper face of the first insulating layer; a first metal layer that is formed on an upper face of the second insulating layer; a third insulating layer that is formed on the upper face of the second insulating layer so as to cover the first metal layer; an opening portion that penetrates at least the second insulating layer, the first metal layer and the third insulating layer in a thickness direction of the wiring board; an electronic component that is provided in the opening portion; a filling insulating layer that fills the opening portion and covers the electronic component; and a wiring layer that is formed on an upper face of the filling insulating layer. A first step portion is formed by a side face of the second insulating layer constituting an inner side face of the opening portion and a side face of the first metal layer constituting the inner side face of the opening portion.