an error detection code decoding device in which information codes obtained through a transmission path and original check codes which correspond to the information codes and which are obtained through the transmission path are input . a processor receives the input information codes and forms restored check codes by using the information codes , the processor including lookup tables for inputting the information codes as addresses and reading out data regarding the restored check codes . a detector detects whether or not the restored check codes and the original check codes coincide and outputs an error detection signal indicative of the presence or absence of an error .