A semiconductor integrated circuit device including a plurality of rows of IO cells has a configuration capable of avoiding a latchup error without causing an increase in area. The device includes a first IO cell row placed closest to an edge of a chip and a second IO cell row placed adjacent to a core region side of the first IO cell row. Each of the IO cells of the first and second IO cell rows has a high power supply voltage region and a low power supply voltage region provided separately in a direction perpendicular to a direction in which the IO cells are lined up. The IO cell rows are placed so that the high power supply voltage regions of these rows are mutually opposed.