WIRING BOARD

A wiring board according to the present disclosure includes an insulation resin layer, and a wiring conductor positioned on the insulation resin layer. The wiring conductor includes a first underlying metal layer, a second underlying metal layer positioned on the first underlying metal layer, a wiring metal layer positioned on the second underlying metal layer, a tin layer positioned covering the first underlying metal layer, the second underlying metal layer, and the wiring metal layer, and a silane coupling agent layer positioned covering the tin layer. When the wiring conductor is seen in a cross section in a width direction, the wiring metal layer includes, from the first underlying metal layer side, a portion with a width narrower than a width of the first underlying metal layer, a portion with a width equal to the width of the first underlying metal layer, and a portion with a width wider than the width of the first underlying metal layer.