In a layout structure of a standard cell including off transistors 126, 127 unnecessary for logic operation of a circuit, dummy via contacts 116, 117 are disposed on impurity diffusion regions 103, 106 of the off transistors 126, 127, respectively. Dummy metal interconnects 122, 123 are connected to the dummy via contacts 116, 117, respectively. Thus, variations in the density of via contacts, which are one of causes lowering the production yield of semiconductor integrated circuits, is reduced, improving manufacturing defects of the via contacts.