An image interpolation apparatus includes: a first processing unit which calculates an error on image data between a patch to be interpolated that overlaps with a masked region and a reference patch that does not overlap with the masked region; a second processing unit which calculates, based on the image data, feature quantities indicating the degrees of flatness of the respective patch regions; a third processing unit which calculates an error between their feature quantities; a fourth processing unit which selects a reference patch that has produced a least significant error based on results obtained by the first and third processing units; and a fifth processing unit which pastes pixel data of the reference patch that the fourth processing unit has selected onto the patch to be interpolated. The third processing unit calculates an error between the feature quantities by comparing the feature quantity of the patch to be interpolated outside of the masked region to that of the entire reference patch.