An image processing apparatus includes an imaging unit which captures an image, and a focal range control unit which changes a focal position and a depth of field of a captured image by controlling an imaging device or a focus lens in the imaging unit. Further, the image processing apparatus includes a distance measurement unit which measures a distance to a subject, from a degree of blur in each of n images (where n ≧2) captured by the imaging unit controlled by the focal range control unit and having focal ranges different from each other.