In a method of detecting motion of a particular part from a sequence of successive input images, motion vectors of a plurality of parts of the input images are detected by tracking feature points in the successive input images, the motion of the particular part is detected by processing the motion vectors. The motion detection is performed by producing a histogram of the motion vectors, detecting a peak corresponding to the particular part from the histogram; classifying feature points into a class of feature points belonging to the peak detected in the histogram processing step and a class of the other feature points, and calculating motion of the particular part by analysing the motion vectors belonging to the peak detected in the histogram processing step. The histogram processing step includes detecting the peak corresponding to the particular part on the basis of the class information defined for feature points.