<p>An improved learning machine having a plurality of multi-input/single-output signal processing units (3) connected in a hierarchical structure comprises a weight coefficient change quantity control unit (30A - 30E) which controls to increase weight change quantities for multi-input/single-output signal processing units (3) involving a large error but not to change weights for multi-input/single-output signal processing units (3) involving a sufficiently reduced error, thereby increasing the learning speed, in contrast with conventional learning machines which perform a learning operation to minimize a square error of multi-input/single-output signal processing units (3) in the highest hierarchy of the hierarchical structure.</p>
