PURPOSE: To improve the versatility of the neural network in solving problems.

CONSTITUTION: The neural network is provided with a neural network arithmetic means 102 where some neurons are connected to multilayer (108, 109, and 110) and learning the relation between input and output signals with teacher signals 106 and 107 based on the learning algorithm, storing the learning result, and performing an arithmetic operation based on the learning result for input signals. The system is provided with a learning algorithm group 104 having several types of learning algorithm. From among several types of learning algorithm 1-n, algorithm to be used for the actual learning is designed to be selected by a learning algorithm selection means 105 according to the problems solved by the neural network arithmetic means 102. Thus, one neural network arithmetic means 102 can perform learning according to problems, resulting in improving versatility.