PURPOSE: To obtain a comparison circuit with in switching operation at high speed, by connecting a resistance between an input and an output of a current Miller.

CONSTITUTION: When the relation of voltages at an input terminal is as as VIN1< VIN2, a current 2I1 of a constant current source Sc flows all to a transistor (TR)Q1. The I1 flows to a diode D1 and another I1 flows to R1 and Q3. Taking the pitential difference between the anode and the cathode of a D1 as VF, a low-level output voltage VL of the output is expressed as VL=VF-R1I1. By setting the R1I1 so that the VL is greater than the saturated voltage of a Q3, the saturation of the Q3 and be avoided and the Q3 can be avoided and the Q3 is at an active area even with the output of low level. Thus, the switching speed from low to high level can be faster. When VIN1>VIN2, the output is at high level and the output voltage VH is VH=VF+ R1I1. Since the anode voltage of the D1 is kept at VF in this case and the anode potential of the D1 is unchanged at switching to a low output state, the speed can be faster.