The present invention relates to an encoding apparatus, an encoding method, an encoding program, a decoding apparatus, a decoding method and a decoding program for encoding and decoding efficiently a video signal in interlace scanning. An adder 12 and a subtractor 13 respectively perform addition and subtraction operations on an odd field and an even field of moving image data in interlace scanning. An intra encoder 14 and an intra encoder 15 wavelet transform addition image data and subtraction image data, quantize transform coefficients W, and entropy encode quantization coefficients q. Encoded data output from the intra encoder 14 and the intra encoder 15 is multiplexed into a single encoded stream to be output. Since data with the addition and subtraction operations performed on the odd field and the even field thereof is encoded, dynamic range is doubled while compression efficiency is increased.