A driver monitoring apparatus comprising: a photographing means for taking a picture of the face of a driver; and an illumination means for emitting light to the face of the driver, characterised by a light amount control means for controlling an amount of light to be emitted from the illumination means so that the amount of light becomes a first amount of light or a second amount of light in synchronisation with a photographing timing taken by the photographing means; a brightness correcting means for creating pre-automatic-brightness-correction image information by subtracting an amount of correction for brightness that has been automatically corrected by the photographing means from brightness in image information obtained from the photographing means; a differential image creating means for comparing image information about a first image on which the face of the driver to which the first amount of light was emitted is photographed with image information about a second image on which the face of the driver to which the second amount of light was emitted is photographed and then creating a differential image from differential information about brightness of corresponding pixels, wherein the image information includes brightness of each pixel of the pre-automatic-brightness-correction image information for the first image and the second image, and wherein the differential information includes a difference in brightness of two corresponding pixels of the first image and the second image; a correcting means for correcting brightness in the differential image created by the differential image creating means; a detecting means for detecting the eyes of the driver from the differential image resulting from correction by the correcting means; and a state detecting means for detecting a state of the driver according to an image of the eyes of the driver. a photographing means for taking a picture of the face of a driver; and an illumination means for emitting light to the face of the driver, characterised by a light amount control means for controlling an amount of light to be emitted from the illumination means so that the amount of light becomes a first amount of light or a second amount of light in synchronisation with a photographing timing taken by the photographing means; a brightness correcting means for creating pre-automatic-brightness-correction image information by subtracting an amount of correction for brightness that has been automatically corrected by the photographing means from brightness in image information obtained from the photographing means; a differential image creating means for comparing image information about a first image on which the face of the driver to which the first amount of light was emitted is photographed with image information about a second image on which the face of the driver to which the second amount of light was emitted is photographed and then creating a differential image from differential information about brightness of corresponding pixels, wherein the image information includes brightness of each pixel of the pre-automatic-brightness-correction image information for the first image and the second image, and wherein the differential information includes a difference in brightness of two corresponding pixels of the first image and the second image; a correcting means for correcting brightness in the differential image created by the differential image creating means; a detecting means for detecting the eyes of the driver from the differential image resulting from correction by the correcting means; and a state detecting means for detecting a state of the driver according to an image of the eyes of the driver.