Disclosed is an optical network unit of an access network for converging broadcast/telecommunication by employing IEEE 1394. The optical network unit processes the broadcast data and the communication data delivered from the optical line terminal according to each corresponding subscriber and delivering the broadcast data and the communication data to each corresponding subscriber. Furthermore, the optical network unit includes a synchronous optical network (SONET) demultiplexer for receiving the broadcast data from the optical line terminal to demultiplex the broadcast data according to each broadcast channel, a broadcast switch part for switching data of each broadcast channel, demultiplexed by the synchronous optical network (SONET) demultiplexer, according to each subscriber unit to deliver the data to each subscriber unit, an Internet protocol (IP) control part for receiving the communication data from the optical line terminal, a main control part for controlling switching with respect to the data according to each channel of each subscriber unit in the broadcast switch part and delivering the communication data from the IP control part to each subscriber unit, a 1394 link layer controller/physical layer controller for converting the data of each broadcast channel delivered from the broadcast switch part and the communication data from the main control part into data of an IEEE 1394 format to deliver the data of the IEEE 1394 format, and an optical transmitting/receiving part for performing optical transmission together with the subscriber units.