An apparatus for detecting and restoring physical identification data (PID) which is the physical position information of sectors arranged on an optical disk, is used in an optical disk recording/reproducing system having a radio frequency amplification unit, includes a pattern detector for outputting an address mark detection signal and a PID pattern upon detecting an AM pattern, and the PID pattern from an eight-to-fourteen modulation (EFM) data stream in the enable section of input signals, a PID error detecting unit for detecting the generation or non-generation of an error by decoding the received PID pattern, and outputting a PID error signal, a sector counting unit for counting the remaining size of a corresponding sector and outputting a counted value as a channel bit clock counting value, a PID window generator for receiving the channel bit clock counting value from the sector counting unit, generating a window signal for PID detection when the counting of a sector is concluded, and outputting the window signal to the AM and PID detector, and a PID continuous determining unit for determining the continuity or noncontinuity of PID by monitoring the input of the address mark detection signal, and outputting a PID position information value, corresponding to a finally received address mark detection signal, to the sector counting unit when the counted value of the error signal is greater than a predetermined threshold value. The apparatus detects and restores for a microcomputer a PID pattern, regardless of degradation and defects of an optical disk (DVD-RAM) surface.