An image processing apparatus is disclosed, which obtains a tomographic image of a tubular body by scanning an inside of a first tubular body using a probe is acquired. Multiple points indicating an inner surface of the tubular body are detected on the tomographic image. Based on a position of the detected multiple points indicating the inner surface, at least one is determined between whether the point indicating the inner surface indicates a first tubular body and the point indicates a second tubular body bifurcated from the first tubular body, and whether the point indicating the inner surface indicates a boundary between the first tubular body and the second tubular body.
