Provided is a video coding method and a video decoding method increasing the resolution and quality of images while suppressing an amount of data required for increasing the resolution. A video coding apparatus includes a first orthogonal transformation unit performing discrete cosine transform on an input picture signal, a low-pass filter performing low-pass filtering on the input picture signal, a downsampling unit downsampling the resolution of a low-frequency image signal, a coding unit compressing and coding a reduced image signal, a local decoding unit decoding a coded bit stream, a second orthogonal transformation unit performing discrete cosine transform on a decoded image signal, and a modification information generation unit generating, based on input image DCT coefficients and decoded image DCT coefficients, coefficient modification information used for modifying orthogonal transformation coefficients obtained by performing orthogonal transformation on a decoded video signal obtained from a coded bit stream.