Image refreshers enhance edge portions of field data stored in field memories, and then store the result in field memories. An intra-field interpolating unit interpolates a moving image pixel using a single piece of field data stored in the field memory, and then stores the moving image pixel in an interpolation memory. An inter-field interpolating unit interpolates a still image pixel using two pieces of field data stored in the field memories, and then stores the still image pixel in an interpolation memory. A still/moving image area determining unit determines whether each pixel of a progressive picture is a still image pixel or a moving image pixel. On the basis of a result of the determination by the still/moving image area determining unit, a selector reads a pixel value in the interpolation memory for a moving image pixel, and reads a pixel value from the interpolation memory for a still image pixel.