PURPOSE: To improve a track density by recording/reproducing data by a plurality of light beams while performing tracking by a first beam-deflecting means.

CONSTITUTION: The apparatus is provided with a first beam-deflecting means 4 for deflecting a first light beam 1 and second light beams 2, 3 and tracking, and a second beam-deflecting means 5 for deflecting only the second light beams 2, 3. Therefore, a distance of light spots is correctly controlled by the second beam-deflecting means 5 while tracking is conducted by the first beam-deflecting means 4, so that a track density is improved. In other words, the distance of light spots is correctly controlled by the second beam-deflecting means 5 while tracking is conducted by the first beam-deflecting means 4, and accordingly a density of tracks 9 is improved.