An image encoding apparatus comprises a separation unit which separates a plurality of planes respectively configured in a single component for a frame of an inputted video; a transform unit which performs a wavelet transformation of a plane of interest in the plurality of planes; an extraction unit which, from each sub-band, extracts in order blocks representing the same region of an image; a quantizing unit which quantizes wavelet transformation coefficients; and an encoding unit which encodes the quantized wavelet transformation coefficients. Here, the quantizing unit includes a determination unit that, for each of the blocks, determines a correction parameter for correcting the quantization parameter based on a direct current value and an alternating current value of the block, and quantizes wavelet transformation coefficients in accordance with the corrected quantization parameter.