A moving vector extractor for detecting a shaking of an image through a video camera in order to improve accuracy of the detection even when the image is dark or of low density gradient as a whole, a density gradient value around representative point is calculated. A basic data of moving vector of the difference value between successive frames is obtained by calculating an absolute value or a squared value. The basic data of moving vector is weighted according to density gradient value so as to improve the precision of moving vector extraction. <IMAGE>
