A multilayer substrate, in which flexible insulating base materials are laminated, includes first and second regions. The number of laminated insulating base materials in the second region is smaller than that in the first region. The multilayer substrate includes a coil antenna located in the first region, a magnetic member located in the first region, a mounting component located in the first region, a wiring pattern, and an external connection terminal. The mounting component entirely overlaps the magnetic member when viewed in a thickness direction and is located on a side opposite to the coil antenna across the magnetic member in the thickness direction. At least a portion of the coil antenna overlaps the magnetic member when viewed in the thickness direction.