Disclosed herein is a semiconductor device including two standard cells which are arranged adjacent to each other in an X direction. One of the two standard cells includes a plurality of first fins which extend in the X direction, and which are arranged along a boundary between the two standard cells in a Y direction. The other standard cell includes a plurality of second fins which extend in the X direction, and which are arranged along the boundary between the two standard cells in the Y direction. The plurality of second fins includes a dummy fin.