<P>PROBLEM TO BE SOLVED: To set optimum recording parameters most suitable to the most likelihood decoding method. <P>SOLUTION: The operation of a reliability value ¾Pa-Pb¾-Pstd of a result of the most likelihood of a part which corresponds to the start and final end parts of an edge of a recording mark and in which occurrence probability is higher in the most likelihood decoding method is performed by each combination of the prescribed mark length and space length immediately before, and each combination of the mark length and space length immediately after, recording parameters optimizing an edge shift position is obtained from the operation result, and recording in which the obtained recording parameter is reflected is performed. <P>COPYRIGHT: (C)2005,JPO&NCIPI 
RECORDING CONTROL UNIT, RECORDING AND REPRODUCING DEVICE, AND RECORDING CONTROL METHOD