An interlace image signal is converted to a progressive image signal. It is decided whether each pixel of one of the first field and the second field is in a static area or a moving area. If a pixel of one field is in the static area, pixel data of the pixel of the one field and pixel data of a corresponding pixel of the other field are output as pixel data of the same pixels of an odd number line and an even number line in the progressive image. If a pixel of the one field is in the moving area, interpolated data of the pixel of the one field and interpolated data of a corresponding pixel of the other field are output as pixel data of the same pixels of an odd number line and an even number line in the progressive image. The interpolated data is filtered pixel data along temporal direction and spatial direction.