Provided are an apparatus and method for coding and decoding a multi-object audio signal. The apparatus includes a down-mixer for down-mixing the multi-object audio signals having different channels to one down mixed audio signal and extracting header information and supplementary information including spatial cue information for each of the multi-object audio signals having different channels, a coder for coding the down mixed audio signal, and a supplementary information coder for generating the supplementary information as a bit stream. The header information includes identification information for each of the multi-object audio signals having different channels and channel information for each of the multi-object audio signals having different channels.