A semiconductor device according to an embodiment of the invention includes: a semiconductor substrate; device regions formed on the semiconductor substrate, the device regions having a length direction in a predetermined direction; a plurality of transistors having gate electrodes, respectively, the gate electrodes extending in a direction approximately perpendicular to the predetermined direction, the plurality of transistors having a source/drain region and a channel region having a channel direction approximately parallel to the predetermined direction in the device region; a plurality of SRAM cells disposed in an array, each of the plurality of SRAM cells including the plurality of transistors; and a dummy region made of the substantially same material as that of the device regions, the dummy region being formed between the outermost device regions of the SRAM cells adjacent to each other in the direction approximately perpendicular to the predetermined direction, the dummy region having a length direction approximately parallel to the predetermined direction.