PURPOSE: To attain the inference by means of a small amount of detailed information by providing an inference circuit which supplies plural analog signals that are linearly related to the confidence coefficients of both minor and major premises of each specific amplitude and then supplies a specific amplitude as an output.

CONSTITUTION: The input signals Xn and Yn correspond to the analog signals that have the amplitudes of 0 or 1, i.e., the confidence coefficients of both minor and major premises or the truth coefficients of correctness. The signal Xn and the current value X are supplied to a negative input terminal 12 of a limit difference circuit 11, and the current of the unit value is supplied to a positive input terminal 13. Then a complementary set Xn' of the signal Xn is applied to the output of the circuit 11 respectively. An output terminal 14 of the circuit 11 is connected to a negative terminal 15 of a limit difference circuit 16, and an input current Yn is supplied to a positive terminal 17 respectively. When the amplitude of the signal Yn is larger than the complementary set of amplitudes of the signal Xn, an analog signal of an amplitude related linearly to the amplitude of the signal Yn is supplied as an output. Otherwise an amplitude of zero is supplied as an output respectively.