There is provided an encoding apparatus. A determination unit determines whether a degree of flatness of pixel values in a first block among a plurality of blocks that compose an image exceeds a predetermined criterion. A selection unit executes processing for selection of an intra prediction mode for the first block. In a case where it has been determined that the degree of flatness in the first block exceeds the predetermined criterion, a control unit controls the processing for selection so as to increase a possibility that the intra prediction mode for the first block is different from each of one or more intra prediction modes for respective one or more reference blocks. An encoding unit applies intra predictive encoding to the first block in accordance with the intra prediction mode selected through the processing for selection.