Volume data is used for extracting a contour of a measurement object and measurement information describing anatomical structure useful for diagnosis is acquired from the contour. When volume data of a subject is inputted (S301), an image processing device detects feature points in the volume data (S302)； detects contours of a plurality of parts in the volume data based on the detected feature points and anatomical definitions (S303)； and optimizes boundary lines defining contours of parts contacting each other, out of the detected plural parts, so as to combine together the optimized contours of the plural parts for creating a contour of the measurement object (S304). Measurements are taken on diagnostic items useful for diagnosis based on the created contour (S305)； and the acquired measurement information is outputted as measurement results (S306) which are displayed at a display.
