A neural network device includes a decimation unit configured to convert a discrete value of an input signal to a discrete value having a smaller step number than a quantization step number of the input signal on the basis of a predetermined threshold value to generate a decimation signal a modulation unit configured to modulate a discrete value of the decimation signal generated by the decimation unit to generate a modulation signal indicating the discrete value of the decimation signal, and a weighting unit including a neuromorphic element configured to output a weighted signal obtained by weighting the modulation signal through multiplication of the modulation signal generated by the modulation unit by a weight according to a value of a variable characteristic.