A module substrate has first and second main surfaces that on opposite sides of the module substrate, a resin member that covers the second main surface, and a plurality of post electrodes that are spaced apart from each other on the second main surface and penetrate through the resin member from the second main surface. The plurality of post electrodes includes a first post electrode and a first recess recessed toward the second main surface and formed in at least part of a region of the surface of the resin member that surrounds a leading end part of the first post electrode.