A decoding device including a decoding unit which decodes encoded data, an inverse orthogonal transformation unit which performs inverse orthogonal transformation for the encoded data and obtains a time series waveform element in a unit of blocks, a correlation calculation unit which obtains a correlation between a time series waveform element of a block arranged immediately before an error block which is a block in which an error has occurred during decoding by the decoding unit and a time series waveform element of a block arranged a predetermined number of blocks before the block, a cycle calculation unit which obtains a basic cycle of a block unit of the error block based on the correlation obtained by the correlation calculation unit, and a generation unit which generates a substitute signal of the time series waveform element of the error block.