There is provided a semiconductor device in which the characteristic variations of a transistor and the degradation of a gate oxide layer are reduced during a WP process and a method for manufacturing the same. The semiconductor device includes a semiconductor chip having an SOI transistor. The SOI transistor includes a semiconductor layer comprising device isolating regions, a channel region, and diffusion regions that sandwich the channel region therebetween. The semiconductor layer is formed on a support substrate via a first insulating layer. A gate electrode is formed on the channel region of the semiconductor layer via a second insulating layer. The semiconductor chip has, on the first surface, a first electrode pad electrically connected to the SOI transistor and a second electrode pad electrically connected to the support substrate.