To realize efficient soft judgment by a soft judging apparatus having a soft decision arbitration value setting function 31 which establishes arbitration values used for the soft decision of received data by which error correction coding is performed, and a soft decision function 32 which performs the soft decision of the received data using the arbitration values.

The soft decision arbitration value setting function 31 detects the maximum value of the level of the received data in every communication frame by receiving data level maximum detection means, averages the maximum value concerned by predetermined equalization system about a plurality of communication frames by a receiving data level maximum averaging means, and establishes the values of the larger one as arbitration values among the values and predetermined threshold as a result of the arbitration values setting means doing division of the maximum by the mean rate. With soft decision function part 32, as a result of soft decision result data formation means doing division of the received data with the arbitration values, the data of predetermined work length of high order are formed as the data of the soft decision result about the values.