PURPOSE: To operate an input signal with a high precision by detecting the difference between the voltage of an input terminal and a preliminarily set reference voltage and performing the control in accordance with the difference output so that the voltage of the input terminal is constant.

CONSTITUTION: A negative feedback circuit 200 adjusts the current of a transistor TR 220 so that the voltage of a current mirror operation circuit input terminal 115 is equal to that of a reference input 211 of an amplifier 210. As the result, not only the voltage of the terminal 115 but also voltages of input terminals 111∼114 where forward voltages are approximately equal are controlled to the same reference value. Consequently, if a voltage V5 which is an approximate average value of operation input voltage V1∼V4 of operation inputs 111∼114 is impressed to the terminal 115, an arithmetic circuit 100 and an output current I0 are not dependent upon the variation of temperature or the like, and the output current I0 is given by I0=f(V1, V2, V3, V4) determined with inputs V1∼V4.