PURPOSE: To make it hard to receive the effect of external noise and to decrease the current consumption, by incorporating the full power supply voltage change detection circuit to the semiconductor integrated circuit.

CONSTITUTION: The sampling signal a for power supply voltage change detection is input to the gate of complementary MOS inverter INV1, and the output of INV1 is fed to the gate of the complementary MOS inverter INV2 and the capacitor C one end of which is connected to the low potential side of the power supply. Further, the change in the power supply voltage is stored MEM via the gate G based on the pulse width of the output signal of INV2 for detection.