Japanese Patent Application Laid-Open Publication No. 2008-118004 (Patent Document 1) describes a layout structure in which a power supply wiring connected to a diffusion layer is drawn onto boundary line between adjacent standard cells. More specifically, Patent Document 1 describes a layout structure in which a diffusion layer is shared between adjacent standard cells and a wiring is drawn from a power supply wiring onto boundary line between the adjacent standard cells. And, Patent Document 1 describes a structure in which the wiring drawn on the boundary line between the adjacent standard cells and the diffusion layer shared between the adjacent standard cells are electrically connected to each other via a plug.