Disclosed is an information processing system having a neural processing unit, an expert system for executing an inference using a rule, and an information selection unit. The neural processing unit and the expert system being arranged in parallel to each other. The information selection unit selects and outputs necessary information from the information outputted from the neural processing unit and the expert system. Since necessary information is selected and outputted from the information obtained from the neural processing unit and the expert system as a result of processing executed by the neural processing unit and the expert system in the parallelly different points of view, the certainty of the information to be selected is improved.