To mount a plurality of module substrates on a mother board in a short time.

A plurality of module substrates 2, 3 are laminated and disposed and the module substrates 2, 3 are connected and integrated by using a heat-softening adhesion part 7, for example. Since the plurality of module substrates 2, 3 are connected and integrated, they can be carried onto a mother board 15 at once. The time required for mounting process can be greatly reduced when compared to that for carrying them onto the mother board one by one. When the module substrates 2, 3 of a stacking structure are mounted on the mother board 15, even if there is a floating terminal 5 to a junction member 16 for terminal connection on the mother board 15 caused by strain or the like of the mother board 15, the heat-softening adhesion part 7 softens by heat of heating treatment for dissolving the junction member 16 and the module substrates 2, 3 can perform self-correction for their attitude to eliminate floating of the terminal 5 by their own weight.