Semiconductor device

Plural I/O cells having electrode pads for wire bonding are disposed with spaces between them in the vicinity of a corner of an I/O region of a semiconductor substrate, and power supply separation cells not to be wire bonded, on which ESD (electrostatic discharge) protection circuits having ESD protection transistors are amounted, are disposed between the respective I/O cells, whereby the chip size is reduced upon consideration of layout of the electrode pads.