A technology that makes it possible to reduce fluctuation in operating voltage for operating the circuits formed in the core region of a semiconductor device is provided. This semiconductor device is so arranged that the core region is divided into multiple functional blocks and power can be supplied and this power supply can be interrupted with respect to each of the divided functional blocks. The core region formed in the semiconductor chip is divided into multiple functional blocks. A power switch row in which multiple power switches are arranged is disposed in the boundaries between the divided functional blocks. These power switches have a function of controlling the supply of reference potential to each of functional blocks and the interruption of this supply. A feature of the invention is that reference pads are disposed directly above the power switch rows. This shortens the wires coupling together the reference pads and the power switches.