Abstract: A semiconductor device comprising a laminate of plural insulating substrates 101 to 104 on which are mounted semiconductor chips (electronic parts) 12, wherein, when the lower-most insulating substrate is regarded to be a first insulating substrate 101 and other insulating substrates to be second insulating substrates 102 to 104 among the insulating substrates that are laminated; second electrically conducting wirings 112 to 114 are so provided as to protrude beyond the peripheral edges of the second insulating substrates and are folded toward the side of other surfaces of the second insulating substrates, and the thus folded second electrically conducting wirings are electrically connected to the electrically conducting wirings on the lower insulating substrates.