PURPOSE: To prevent malfunction due to noise by causing a constant current to flow to a resistive element corresponding to the output of a comparator circuit to set a Schmitt width optionally depending on a noise level from an equipment itself employing the comparator circuit or from a peripheral equipment.

CONSTITUTION: The comparator circuit is constituted by adding an inverter 21 whose noninverting input terminal 2 is connected to a resistive element 8 with respect to gate of MOSFETs 12, 15, and whose input terminal is connected to an output terminal 23, a P-channel MOSFET 6 whose gate is connected to a gate of a MOSFET 3, an a P-channel MOSFET 7 whose gate is connected to the output terminal of the inverter 21 and which is inserted between the P-channel MOSFET 6 and a resistive element 8. The Schmitt width is set optionally depending on a noise level from an equipment itself employing an integrated circuit incorporating the comparator circuit or from a peripheral equipment by causing a constant current to flow to the resistive element 8 in response to the logic level of the output of the comparator circuit.