PURPOSE: To provide the CMOS operational amplifier almost fixing current consumption to a temperature change.

CONSTITUTION: A resistor 51 having a positive temperature coefficient is serially connected to one P channel MOS transistor 34 at least in respect to two P channel MOS transistors 31 and 34 to decide the current consumption of the CMOS operational amplifier by impressing a bias voltage. The resistor 51 having the positive temperature coefficient compensates the temperature characteristic of the P channel MOS transistor 34 to decide the current consumption and fixes the current consumption of the CMOS operational amplifier in respect to the temperature. Therefore, the current consumption of an entire semiconductor integrated circuit equipped with the CMOS operational amplifier does not depend on the temperature as well, and the demerit of shortening the service life of a battery at a high temperature is canceled.