PURPOSE: To discharge heat generated from a semiconductor element uniformly, and to miniaturize the device while improving reliability by forming an insulating plate or a metallic plate onto both surfaces of the element through insulating resin.

CONSTITUTION: An electrode lead 4 on a polyimide resin film 3 is positioned onto electrodes 2 on the semiconductor element 1, and pressed and joined. A coating material in epoxy resin 12, etc. and the metallic plates or the insulating plates 10, 10' are contacted from the upper and lower sections of the semiconductor 1 joined to the electrode lead 4 and pressed, and heated, thus curing the resin, then sealing up the semiconductor element. In this case, the resin may be liquefied or laminar, its thickness is 1μm or thicker when it is laminar, and it is applied previously onto the surface of the semiconductor surface or the insulating plates 10, 10' when it is liquefied. The thickness of the metallic plates or the insulating plates may be 50μmW0.5mm.