PURPOSE: To automatically extract the continuous outline of a body by the body outline tracking method for extracting the part of the body from the image.

CONSTITUTION: As for the body outline tracking method which tracks the outline of the body from one point on the outline of the body in the image as a start point, the start point of the outline of the body is specified and respective pixels in an area within a specific range from the pixel specified as the start point are regarded as outline candidate points; and points on the outline are decided among the outline candidate points according to the respective outline candidate points and image data showing the colors of pixels at the periphery of each of the outline candidate point. When a obtained point on the outline does not match the start point, respective pixels in an area within the specific range from the point on the outline are regarded as outline candidate points and points on another outline are decided among those outline candidate points; when an obtained point on the outline match the start point, the outline tracking process is ended.