A multilayer substrate includes a plurality of stacked thermoplastic resin layers each including an in-plane conductive pattern provided on one principal surface thereof and an interlayer conductive portion arranged to penetrate through the thermoplastic resin layer in a thickness direction. The plurality of thermoplastic resin layers include a first thermoplastic resin layer and a second thermoplastic resin layer, a stacking direction of which is inverted with respect to a stacking direction of the first thermoplastic resin layer. The second thermoplastic resin layer is thicker than the first thermoplastic resin layer. One end in the thickness direction of the interlayer conductive portion provided in the second thermoplastic resin layer is connected with the interlayer conductive portion of the thermoplastic resin layer adjacent to the second thermoplastic resin layer in the thickness direction such that the in-plane conductive pattern is not interposed therebetween.