Provided is an apparatus for transferring optical data in an optical switching system using time synchronization. The apparatus performs time synchronization on optical data to input the optical data at regular intervals through fiber delay line for time synchronization respectively disposed on input ports. Therefore, the apparatus can efficiently reduce a data blocking rate in comparison with a conventional optical switching system using an asynchronous electric buffer without a synchronous process, and achieve the same performance as conventional asynchronous technology despite using fewer wavelength converters and buffers, thus reducing system cost. In addition, using dynamic time synchronization modules, the apparatus performs time synchronization for minute time variation due to an environment such as temperature.