Wiring board, laminated wiring board, and semiconductor device

A wiring board comprising:

• a first interconnect layer;
• a first insulating layer covering the first interconnect layer;
• a second interconnect layer, thinner than the first interconnect layer, formed on a first surface of the first insulating layer, the second interconnect layer having an interconnect density higher than an interconnect density of the first interconnect layer;
• and
• a second insulating layer, formed on the first surface of the first insulating layer, and covering the second interconnect layer,
• wherein the first insulating layer includes a first layer including no reinforcing material and located on a side closer to the first interconnect layer, and a second layer laminated on the first layer and including a reinforcing material,
• wherein the first layer and the second layer respectively include a non-photosensitive thermosetting resin as a main component thereof,
• wherein the first layer has a coefficient of thermal expansion higher than a coefficient of thermal expansion of the second layer,
• wherein the second insulating layer includes a photosensitive resin as a main component thereof, and
• wherein the second interconnect layer includes an interconnect formed directly on the first surface of the first insulating layer and electrically connected to the first interconnect layer.