Wiring board

A wiring board comprising:

• a film made of resin;
• a first insulating layer located above the film and including a first groove;
• a first wire provided in the first groove, the first wire being conductive;
• a second insulating layer located above the first insulating layer and including a second groove and an opening, the opening being located above the first wire;
• and
• a second wire provided in the second groove and the opening, the second wire being conductive, wherein
• the first groove includes a first base face and first lateral faces that are continuously connected to the first base face,
• in the first base face and the first lateral faces, the first insulating layer is made of a same material,
• the second groove includes a second base face and second lateral faces that are continuously connected to the second base face,
• in the second base face, the second lateral faces, and a lateral face of the opening, the second insulating layer is made of a same material, and
• a top face of the first wire and a bottom face of the second wire that is provided in the opening are joined to each other.