In a module substrate, a plurality of terminal connection substrates each including an insulator and a plurality of columnar terminal electrodes arranged on a single lateral surface or both lateral surfaces of the insulator is mounted on a single side of a composite substrate such that at least one of the terminal connection substrates extends over a border between a plurality of neighboring module substrates. The composite substrate, in which the plurality of terminal connection substrates is mounted on the single side and a plurality of electronic components is mounted on at least the single side, is divided at a location where the module substrates are to be cut from the composite substrate.