A semiconductor integrated circuit includes: a main-interconnect to which supply voltage or reference voltage is applied; a plurality of sub-interconnects; a plurality of circuit cells configured to be connected to the plurality of sub-interconnects; a power supply switch cell configured to control, in accordance with an input control signal, connection and disconnection between the main-interconnect and the sub-interconnect to which a predetermined one of the circuit cells is connected, of the plurality of sub-interconnects; and an auxiliary interconnect configured to connect the plurality of sub-interconnects to each other.