PURPOSE: To use the signal change of an optional neural circuit network including the changes of the signals immediately preceding signal as the information by changing the prescribed value serving as the arithmetic reference of at least one of various arithmetic elements of the neural circuit network in terms of time and in accordance with the data inputted in time series.

CONSTITUTION: The 1st data D1 on a 2-input AND (D1.AND.D2) is presented to an input neuron 1 and then the 2nd data D2 of the 2-input AND is presented to the neuron 1 respectively. The value of an output neuron 2 obtained after the time when the data D2 is presented to the neuron 1 is defined as the computing result. Thus at least one of various arithmetic elements of the neural circuit network, e.g., the value of the synapse efficiency is changed in terms of time and in accordance with the data inputted in time series. As a result, the value of the synapse efficiency, for example, can be learnt in an optional system in accordance with the data and with no limitation applied to the structure of the neural circuit network.