In order to provide a low-cost and high heat-radiating electronic circuit device featuring high compactness, little warpage, high air tightness, high moldability, high mass productivity, high reliability against thermal shocks, and high oil-proof reliability, a module structure made by packing a whole multi-layer circuit board which connects a semiconductor operating element, semiconductor memory elements, and passive elements thereon and part of a supporting material on which said multi-layer circuit board is placed into a single package by transfer-molding; wherein said multi-layer circuit board and said supporting material are bonded together with a compound metallic material made up from copper oxide and at least one metal selected from a set of gold, silver, and copper.