To provide images of higher image quality when decoding a stream encoded with a standard resolution and converting it to high definition images.

An intra-field pixel interpolation part 33 generates an interpolated pixel using pixels within the same field. An inter-field pixel interpolation part 34 generates an interpolated pixel using pixels in different fields. A weighted average part 35 refers to a prediction mode during the predictive encoding of an encoding stream, increases the mixing ratio of the interpolated pixel by the intra-field pixel interpolation part 33 when the prediction mode is a field prediction mode, increases the mixing ratio of the interpolated pixel by the inter-field pixel interpolation part 34 when the prediction mode is a frame prediction mode, and performs mixing.