There are provided a context-based adaptive binary arithmetic decoding method and apparatus. The context-based adaptive binary arithmetic decoding apparatus includes: a context extractor extracting a plurality of contexts from a storage unit storing contexts each including a state value for probability characteristic; a first ROM table storing current probability information so that a current binary symbol of the bit stream is decoded according to a state value of each context; a second ROM table storing predicted probability information so that a next binary symbol of the bit stream is decoded according to a state value of each context; a general mode arithmetic decoder, which performs pipeline processing, loading current probability information from the first ROM table on the basis of a current state value of a context extracted from the context extractor to decode a first binary symbol, and loading predicted probability information from the second ROM table to decode a next remaining binary symbol while decoding the remaining binary symbols; and a bypass mode arithmetic decoder, including a plurality of calculators for parallel processing, simultaneously decoding a plurality of corresponding binary symbols of the bit stream, to perform arithmetic decoding on the remaining symbols if a predetermined condition is satisfied while the general mode arithmetic decoder performs arithmetic decoding on the corresponding symbols of the bit stream. Therefore, by implementing a hardware suitable for context-based adaptive binary arithmetic decoding, it is possible to enhance a decoding speed.