Abstract: There is disclosed an optical information recording/reproducing apparatus capable of exactly detecting a timing to interrupt recording or reproducing. A threshold value is set with respect to a state detection signal (parameter) indicating an irradiation state with an optical disk 1 such as a focus error signal and a tracking error signal, and the recording or reproducing is interrupted in accordance with a comparison result of the state detection signal with the threshold value. The threshold value set with respect to one state detection signal is set in accordance with another state detection signal.

Abstract: The present invention provides an optical information recording and reproducing apparatus which is capable of performing accurate adjustment of a variety of parameters or offsets in a minimum amount of time, even when vibrations are applied to the apparatus, and even when there are flaws on a recording medium, during adjustment of the recording or reproduction parameters or during adjustment of the offsets in servo control at the time of startup, exchanging the recording medium, and the like. The adjustment of recording or reproduction parameters or offsets of the servo control based on the reproduction index showing the quality of a reproduction signal is performed by correcting or invalidating the reproduction index when there is an abnormality in servo control.