A field pair correlation acquisition part obtains a correlation for six or more fields which are continuous in time series for each field pair formed of two adjacent fields having the same attribute. A first determination part determines an input image as a 2:2 pull-down image based on a determination condition, the determination condition being that a pattern in which the correlation of each of the field pairs of one attribute changes along with a time direction matches a pattern in which the correlation of each of the field pairs of the other attribute changes along with the time direction.