1. A computer system for relieving an operator's fatigue, comprising: an input device for capturing the operator's face to generate image data representing the face; an image processing circuit connected to the input device for creating a model image of the operator's face from the image data; a fatigue determination circuit connected to the image processing circuit for analyzing the model image to determine a fatigue degree of the operator; and an information generator circuit connected to the fatigue determination circuit for generating response information in accordance with a result of the determination.