an optical recording / reproducing apparatus for determining a direction in which an optical pick - up moves , and detecting a track cross signal . the track cross signal is useful as a basis of determining tracking pull - in after searching a track . in the present track cross signal detecting method , the track cross signal is obtained by binarizing the envelope of an rf signal rf 0 obtained by subtracting some light receiving signals generated by some light receiving devices in the radial direction from other light receiving signals generated by other light receiving devices in the radial direction . the light receiving signals originate from a photodetector , divided into two or more sections in the radial direction . the track cross signal detecting method is especially useful for generating the track cross signal when the track pitch is smaller than the size of an optical spot , the signal being less affected by crosstalk caused by an adjacent track .