The present disclosure relates to technology for generating an efficient predicted image by using a correlation between color planes in encoding of a multi-plane video. An apparatus for encoding a multi-plane video including two or more color planes by using a bi-prediction includes: an intra-predictor for generating a first predicted block by performing an intra-prediction on a current block of a current plane; an inter-plane predictor for generating a second predicted block by performing an inter-plane prediction; a dual-plane predictor for generating a third predicted block based on the first predicted block and the second predicted block; an optimum mode determiner for selecting one optimum predicted block having a highest encoding efficiency from the first to third predicted blocks; and an encoder or a decoder for encoding or decoding the current block based on a selected optimum predicted block.