The SOI substrate 1 has a supporting substrate 10, an insulating layer 20 formed on the supporting substrate 10 and a silicon layer 30 formed on the insulating layer 20. A through electrode 40 is provided in a device formation region A1 of the SOI substrate 1. The through electrode 40 reaches the insulating layer 20 from the silicon layer 30. Specifically, the through electrode 40 extends to an inner part of the insulating layer 20 originating from a surface of the silicon layer 30 while penetrating the silicon layer 30. Here, an end face 40a of the through electrode 40 at the insulating layer 20 side stops inside the insulating layer 20.