A module component includes a substrate; first, second, third and fourth main electrodes on or in a principal surface of the substrate; a sub-electrode located between two of the four main electrodes and connected to one of the four main electrodes by a solder; a first mount component mounted to the first and second main electrodes; and a second mount component mounted to the third and fourth main electrodes; wherein an area of the sub-electrode is smaller than an area of each of the first, second, third and fourth main electrodes.