PURPOSE: To obtain a semiconductor integrated circuit in which a power switch circuit can be turned ON/OFF only with a small number of external or internal signals by connecting feeder lines, connected with bonding terminals, through the power switch circuit with a circuit block.

CONSTITUTION: A circuit block 14 and a power switch circuit 40 are connected with feeder lines VDD and VSS. The power switch control circuit 40 turns power switch circuits 21, 22 ON/OFF for circuit blocks 11-13 based on a signal delivered from the circuit block 14 or an external signal received through a pad. When the circuit blocks 11-13 are turned ON/OFF independently, power consumption can be reduced as compared with a case where the circuit blocks 11-13 are turned ON/OFF simultaneously. Consequently, the power switch circuit can be turned ON/OFF with small number of external or internal signals.