A printed wiring board assembly includes a first board including a first surface; a second board including a second surface and facing the first surface; a plurality of first electrodes formed on a bottom surface of a recess formed in one of the first and the second surfaces; a plurality of second electrodes formed on the one of the first surface and the second surface and positioned outside the recess; a plurality of first solders each coupled to a respective one of the plurality of first electrodes; and a plurality of second solders each coupled to a respective one of the plurality of second electrodes, wherein the plurality of first electrodes are formed at a larger pitch than a pitch at which the plurality of second electrodes are formed, and a size of each the plurality of first solders is larger than a size of the plurality of second solders.