1. A multi-class discriminating device, for judging which class out of plural classes a feature represented by data falls into, comprising: a first hierarchical discriminating-device generating unit for generating plural first hierarchical discriminating devices each for discriminating one from N; and a second hierarchical discriminating-device generating unit for combining score values output respectively from the plural first hierarchical discriminating devices to generate a second hierarchical feature vector, and for entering the second hierarchical feature vector to generate plural second hierarchical discriminating devices each for discriminating one from N, wherein when data is entered, the plural first hierarchical discriminating devices output score values respectively, and these score values are combined to generate the second hierarchical feature vector, and when the second hierarchical feature vector is entered, the second hierarchical discriminating device which outputs the maximum score value is selected from among the plural second hierarchical discriminating devices, and the class corresponding to the selected second hierarchical discriminating device is discriminated as the class, into which the feature represented by the entered data falls.