DIAGNOSING METHOD OF GOLF SWING

A camera 10 photographs a golf player swinging a golf club to hit a golf ball and the golf club. Image data is obtained by photographing. A calculating part 16 extracts a plurality of frames from the image data. The calculating part 16 determines a check frame in which the golf player is in a predetermined posture from the plurality of frames. The calculating part 16 determines a contour of the golf player from the check frame. The calculating part 16 decides a swing from the contour of the golf player. An extreme value constituting the contour is determined in deciding the swing. A feature point is determined from the extreme value. The swing is diagnosed using the feature point.