Pits and lands which have a pit length of 3T, a land length of *6T, a pit length of 7T, a land length of *3T, a pit length of 6T and a land length of *7T are alternately formed in a lead-in area in an inner track area on an optical disk as a test pattern for evaluating a read error of the optical disk. This test pattern data is reproduced by a reproducing system to detect an error rate, a compensation coefficient for minimizing the error rate is acquired, and a reproduction signal is compensated by using this compensation coefficient so that the reproduction signal is reproduced with the minimized error rate by the reproducing system.