PURPOSE: To provide a two-sided optical disc recorder/reproducer in which information can be written in and read out simultaneously on two sides regardless of the loading direction of the optical disc.

CONSTITUTION: An optical disc 1 is loaded onto a turn table 3 by means of a clamper 2 and information is written in and read out simultaneously through optical head sections 6a, 6b disposed on both sides of the optical disc 1. Side A indicating part or side B indicating part provided at a part of the optical disc 1 is then read out through the optical head sections 6a, 6b and the rotating direction of a spindle motor 4 for driving the optical disc 1 is then controlled through a motor control section 5 depending on thus read out results. By this constitution, information can be written in or read out from the optical disc 1 regardless of the loading direction of the optical disc 1.