PURPOSE: To simultaneously execute scaling for extending and contracting the ranges of an input value and an output value and level shifting in the input part and the output part of fuzzy inference hardware by providing a means for extending/contracting the scale of the input value and for shifting a level.

CONSTITUTION: In a fuzzy inference system using a MIN-MAX-centroid method as an inference method, the ranges are changed so that they are fitted to a controlled system and a target by using a scaling circuit/level shift circuit 10 when n pieces of labels in input 1 to input (n) are not matched with the input of an adaptability computing element 20. The output of the circuit 10 which is made matched is inputted to the adaptability computing element 20, and the adaptability of input and an antecedent part is obtained. A minimum value computing element 30 performs the minimum value operation of the obtained adaptability and a consequent part, and inference results for respective inference rules are obtained. The respective inference results are synthesized in a maximum value computing element 40, and a decided value is outputted from the inference result as a final output value in a non-fuzzy circuit 50.