To provide the neural network of a structure in which the accuracy of prediction/diagnosing or the like is high and appropriate analysis is possible as well.

The neural network structure of a previous application (patent application 2000-230665) is a prerequisite and the structure is provided with product coupling partially further. As being partially, the structure is provided with the product coupling only in the intermediate layer element of a fully coupled part 20 for instance. The analysis of the neural network in the previous application is the method of analyzing the input/output characteristics of a loosely coupled part and the fully coupled part is a part difficult to be analyzed like before. That is, since the product coupling is provided only in the part difficult to be analyzed, the generation of unrequired coupling is suppressed, generalization ability is improved and the increase of learning time is minimized. Also, though the coupling of product components is complicated and tends to be difficult to be analyzed, since the product components are not provided in the loosely coupled part of an analysis object, the analysis is facilitated.