In order to point out certain suggestions useful in skill instruction of diving action in racing swim, the bodily action was analyzed upon taking a 16mm movie. The findings may be summerised as follows; 1)During the "get set" moment, placing the center of gravity high and close to the front edge of the starting table would give some advantages for the swimmer. 2)At the moment when knees are flexed maximally during the starting action, placing the center of gravity close to the front edge of the starting table is advised. 3)Exertion of strong enough power in explossively extending the knees and hips from the point when these two joints are flexed maximally would be the key for the effective diving action. 4)The direction of take-off is often suggested to be slightly upward. While the major factor to determine this direction lies in the extension action of knees and hips, the snapping action at the ankle joint seems also to have some implication in controlling the direction of take-off. 5)Hyperextention of body during the flight after take-off may be acceptable, if the body is maintained reasonably straight at the moment of body entering into water.