PURPOSE: To easily visualize the result of inference by displaying a fuzzy inference result value using an edited fuzzy rule and a membership function in a graph, a two-dimensional image, or three-dimensional graphics. CONSTITUTION: A fuzzy inference knowledge generating means 31 describes the numeric value of a certain item in a fuzzy rule represented in a form of if-then and the membership function defining the meaning of propositions being described on an if part and a then part. A parameter setting means 32 for knowledge verification sets the minimum value, the maximum value, numeric value width, and a value (representative value, adaptation. or computed result) employed as the fuzzy inference result as a parameter for knowledge verification. A fuzzy inference function 33 performs fuzzy inference for verification according to generated fuzzy knowledge and set every kind of parameter. A display output function 34 displays the inference result value in the two-dimensional image or the three-dimensional graphics. COPYRIGHT: (C)1993,JPO&Japio