A write type optical disk device with the PRML mode allows accuracy in the trial writing to be improved accompanied with the high speed processing while assuring the readout compatibility. A readout signal that has been A/D converted at timing that interposes the edge has its phase compensated with the even numbered FIR filter. The level at the edge point and the absolute values thereof are accumulated respectively so as to provide a circuit for detecting the edge shift and jitter. Coping with the high speed processing, the edge shift of the readout signal is detected at the position where the edge shift is around zero, thus improving the accuracy in learning of trial writing.