Abstract: A computer system that executes computation processing using a recurrent neural network constituted with an input unit, a reservoir unit, and an output unit. The input unit includes an input node that receives a plurality of time-series data, the reservoir unit includes a nonlinear node accompanying time delay, the output unit includes an output node calculating an output value. The input unit calculates a plurality of input streams by executing sample and hold processing and mask processing on a plurality of received time-series data, executes time shift processing that gives deviation in time to each of the plurality of input streams and superimposes the plurality of input streams subjected to the time shift processing, thereby calculating input data.