Disclosed is a method for manufacturing a wiring structure including a step of forming a wiring on an insulating resin layer. The step of forming the wiring includes: forming a modified region including pores in a surface layer of the insulating resin layer by treating a surface of the insulating resin layer with a treatment method including surface modification; forming a seed layer on the surface of the insulating resin layer by sputtering; and forming the wiring on the seed layer by electrolytic copper plating.