A semiconductor device includes a semiconductor substrate having a first electronic circuit and a second electronic circuit formed on an active surface, a pad electrode formed on the active surface by being connected to the first electronic circuit and/or the second electronic circuit, a first opening formed to some point along a depth of the semiconductor substrate toward the pad electrode from a surface opposite to the active surface of the semiconductor substrate, a second opening formed so as to reach the pad electrode from a bottom surface of the first opening, an insulating layer formed by covering sidewall surfaces of the first opening and the second opening, a conductive layer formed by covering at least an inner wall surface of the insulating layer and a bottom surface of the second opening, a third opening formed to some point along the depth of the semiconductor substrate from the surface opposite to the active surface of the semiconductor substrate, and a heat insulator imbedded in the third opening.