A semiconductor integrated circuit device includes a first power wiring that is formed on a semiconductor substrate and that extends in a first direction, a second power wiring that extends in the first direction such that the second power wiring is separated from the first power wiring, a first diffusion layer that is used for a p-channel type MOSFET and that is formed in a region between the first power wiring and the second power wiring, a second diffusion layer that is used for an n-channel type MOSFET and that is formed on a side of the second power wiring with respect to the first diffusion layer in the region between the first power wiring and the second power wiring, a first gate electrode that extends in a second direction perpendicular to the first direction and that straddles the first diffusion layer, a second gate electrode that extends in the second direction and that straddles the second diffusion layer, and a third diffusion layer for backgates that is formed below at least one of the first power wiring and the second power wiring and that is placed in a dotted manner along the first direction.