An image processing apparatus includes: a blood vessel sharpness calculation unit configured to calculate blood vessel sharpness representing sharpness of a visible vascular pattern in a mucosa region in which a mucosa in a lumen is shown in an intraluminal image an abnormal candidate region extraction unit configured to extract a sharpness reduction region in which the blood vessel sharpness is reduced, as a candidate region for an abnormal region in which the visible vascular pattern is locally lost and an abnormal region determination unit configured to determine whether the candidate region is the abnormal region based on a shape of the candidate region.
