PURPOSE: To decrease a through-current by inserting a switching element to a power and ground side of a CMOS inverter having a large driving capability and adding a CMOS inverter circuit with a small driving capability in parallel with said inverter circuit.

CONSTITUTION: The source of a P-channel MOS transistor(TR) with a large driving capability is connected to a power supply via a switching element 8 and the source of an N-channel MOS TR with a large driving capability is connected to ground via a switching element 9 respectively, and the source of a P-channel MOS TR 5 with a small driving capability is connected to a power supply and the source of an N-channel MOS TR 6 with a small driving capability is connected to ground respectively and the control signal input of switching elements 8, 9 interrupted by a high level is connected to the output of a differentiation circuit 7. Since driving capability of the MOS TRs 5, 6 are smaller than that of the MOS TRs 3, 4, the through-current is made very small.