PURPOSE: To easily realize LSI and to improve the capability of a neural network by providing a coupling constant evaluation correction part and virtually varying a coupling constant.

CONSTITUTION: An input signal {x1} composed of N pieces of elements of input signals x1, x2... xN is supplied to an input layer 5, and an output signal {zK} composed of the M pieces of elements of output signals z.1, z2... zM is outputted from an output layer 9. A signal suggestion part 11 suggests an input signal {I1} (i=1, 2,...N) against the input layer 5, and suggests the required output signal of the output layer 9 corresponding to the input signal supplied to the input layer 5 against a coupling constant evaluation correction part 13, that is, a teacher signal {O1} (k=1, 2,...M). The coupling constant evaluation correction part 13 varies the coupling constant virtually, and corrects the coupling constant based on the input signal {I1} suggested by the signal suggestion part 11 and a teacher signal {0K} corresponding to this. Thus, the LSI can be easily attained and the capability of the neural network can be improved.