PURPOSE: To reduce an area occupied in an integrated circuit by equivalently forming a resistor between an input side where the input signals of an input transistor are added and a grounding by using a current mirror circuit.

CONSTITUTION: A mirror current is respectively supplied from a first current mirror circuit to the input transistor Q1 and a second current mirror. The mirror current is set by a constant current source S1 and a base current for the portion of the mirror current is shunt from the base of the input transistor Q1 to which the input signals are added to the grounding. When the input signals are added and the base current to be made flow to the base of the input transistor Q1 is less than the mirror current, the input transistor Q1 is turned off and the output of an H level is obtained in an output terminal 2. Then, the second current mirror circuit plays the role of the resistor and it is equivalent to that the resistor is connected between the base of the input transistor Q1 and the grounding. The resistance value can be adjusted by the current of the constant current source S1.