First and second semiconductor layers are attached to each other with an insulation layer sandwiched therebetween. An acceleration sensor device is formed in the first semiconductor layer. A control device for controlling the acceleration sensor device is formed on the second semiconductor layer. Through holes are formed in the second semiconductor layer, and an insulation layer is formed to cover the wall surfaces of the through holes. Through interconnections are formed within the through holes for electrically connecting the acceleration sensor device and the control device to each other. Accordingly, it is possible to obtain an acceleration sensor having excellent detection accuracy while having a reduced size, and a fabrication method thereof.