WIRING SUBSTRATE

A wiring substrate includes an insulating layer including a first layer and a second layer, and a conductor layer including a metal film formed on a surface of the second layer of the insulating layer such that the conductor layer includes a conductor pattern. The first layer includes resin and first inorganic particles, the second layer includes resin and second inorganic particles at the content rate that is lower than the content rate of the first inorganic particles in the first layer, and the thickness of the first layer is 90% or more of the thickness of the insulating layer. The second layer of the insulating layer includes a composite layer having the thickness in the range of 0.1 to 0.3 μm, and the composite layer includes part of the metal film in the conductor layer formed in gaps between the second inorganic particles and resin in the second layer.