A two-dimensional bit image generated by the input device is processed by a four-layer neural network and recognized. The neurons in the second layer are connected only to the neurons of the first layer aligned in a specific direction, thereby enabling the second layer to extract line components in specific directions. The second layer is further divided into plural regions, and all neurons in each region are connected to one corresponding neuron in the third layer. The output of the third layer neurons thus express the position and degree of the extracted line component in the image. All of the neurons in the third layer are connected to all of the neurons in the fourth layer, and image recognition is possible by learning.