Disclosed are an error-detecting encoding apparatus for creating parity bits by error-detecting encoding
processing, appending the parity bits to an input data string and encoding the data string, and an error-detecting decoding apparatus for detecting error using these parity bits. Data segmenting means segments an input data string, which is to undergo error-detecting encoding, into a plurality of sub-data strings, dividing means divides the segmented sub-data strings by a polynomial, which is for generating an error-detecting code, and calculates remainders, converting means applies conversion
processing, which conforms to a segmentation position of the sub-data strings, to the remainders on a per-remainder basis, and combining means combines converted values, which have been obtained by the conversion
processing, and outputs parity bits. An
encoder appends this parity to a data string, and a decoder detects error using this parity.