Disclosed is a technique for detecting whether dazzling is affecting the drivers driving ability when the eye area is included in the area to which the direct sunlight is incident. More particularly of the technique detects a facial area and an eye area of a driver's image, and an area to which direct sunlight is incident in the facial area, and then determines whether dazzling is effecting the drivers driving ability when the eye area is included in the area to which the direct sunlight is incident to detect a direction of incidence of the direct sunlight and then, automatically blocks the direct sunlight in the direction to which light is incident via a blocking apparatus.