If the picture that includes the blocks p and q is a P picture, the filter processing control unit 110 checks to see if (i) the blocks p and q refer to the same reference picture and (ii) each difference between vertical components (V(p,y) and (V(q,y)) and horizontal components (V(p,x) and (V(q,x)) of the motion vectors of the respective blocks p and q is less than one pixel (Step S208), on the ba