Provided is a method for forming a through-hole including: forming a laminated body including a fluororesin layer having a first main surface and a second main surface, a first adhesive layer, a first reinforcing resin layer and a first conductor layer provided on the first main surface, a second adhesive layer, a second reinforcing resin layer and a second conductor layer provided on the second main surface; forming an opening in the first conductor layer and irradiating the opening with a laser beam to form a bottomed conduction hole with the second conductor layer exposed on a bottom surface of the conduction hole, wherein a thermal decomposition temperature of the second cured adhesive layer is lower than those of the first reinforcing resin layer and the second reinforcing resin layer, and a thickness of the second cured adhesive layer is 10 μm or more and 200 μm or less.