According to one embodiment, a processing device is configured to process input data formed of a plurality of input digital values. The processing device has a plurality of computation layers connected in series. Each of the computation layers has a plurality of computation devices. Each of the plurality of computation devices in the computation layer of a first stage is configured to generate a digital value from the input digital values and weight coefficients defined in advance. The weight coefficients are applied to each of the input digital values. Each of the plurality of computation devices of the computation layer of a second or subsequent stage is configured to generate a new digital value from the digital values generated by the computation devices of the computation layer of the previous stage and weight coefficients defined in advance. The weight coefficients are applied to each of the digital values.