An inspection method for judging whether an object is defective or not uses a neural network comprising an input neuron which quantizes input feature quantities based on present quantization ranges, a plurality of intermediate neuron coupled to the input neuron with coupling coefficients determined from quantized feature quantities and a pair of output neurons coupled to respective intermediate neurons with intermediate coupling coefficients obtained by learning in which the intermediate coupling coefficients are initially set so that any object is judged to be defective and are fitted so that if an object is nondefective then it is judged to be nondefective by performing learning with use of nondefective objects.
