PURPOSE: To easily mount a genetic algorithm for the update of parameters as the coupling coefficient and threshold value of the neural network by substituting an optional random number for the value of a gene seat at the time of mutation processing.

CONSTITUTION: Coupling coefficients W and threshold values θ of neurons 3 constituting the neural network are regarded as constituent elements of a gene 5. Then, one gene 5 is constituted by regarding all coupling coefficients W and threshold values θ in the neural network as the values of the gene seat 6. In this case, the coupling coefficients W and threshold values θ are arrayed on the linear gene 5 at random. The values of the gene seat 6 are real numbers. The real number values are regarded as one element and intersection operation between genes is performed as usual. In mutation operation between next genes, an optional random number is substituted for a value as to a gene seat 6 whose mutation is determined to perform conversion to a value different from the current value.