Wiring board

A wiring board comprising:

• an insulation resin layer;
• and
• a wiring conductor positioned on the insulation resin layer,
• wherein the wiring conductor comprises:
• 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, and
• when the wiring conductor is seen in a cross section in a width direction, the wiring metal layer comprises, 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.