There is provided an apparatus for interpolating a lesion area when diagnosis is performed in a Computer Aided Diagnosis (CAD) system using consecutive images. According to an example, the apparatus includes: an image receiver configured to receive images sequentially; an image matcher configured to match a current image with reference images, and to determine whether to interpolate a lesion area in the current image based on a matching result; and a lesion area acquirer configured to interpolate or acquire the lesion area in the current image according to a result of the determination.