MULTILAYER SUBSTRATE

PROBLEM TO BE SOLVED: To suppress drop of reliability of interlayer connection in a thermoplastic resin film layer.SOLUTION: A multilayer substrate has a thermoplastic resin film layer 10 including an intermediate layer film 110 and adhesive layer films 120, 130 which are laminated and formed of thermoplastic resin, and pattern layers 20 and 30 which are laminated on the surface of the thermoplastic resin film layer 10 and contains thermosetting resin films 21 and 31. The thermoplastic resin film layer 10 comprises a pair of adhesive layers 12 and 13 and an intermediate layer 11 between the pair of adhesive layers 12 and 13. A first interlayer connection portion 11a is formed in the intermediate layer 11, and the pair of adhesive layers 12 and 13 are respectively provided with second interlayer connection portions 12b and 13b which are electrically conducted to the first interlayer connection portion 11a. Conduction patterns 211b, 311b, 114 and 115 are formed on at least one of surfaces of the pattern layers 20 and 30 and the intermediate layer 11 which face the second interlayer connection portions 12b and 13b.