In an apparatus and method for transferring data bursts in an optical burst switching network, a control module connected between demultiplexers and multiplexers obtains information in control packets of data bursts to sort and confirm service classes of the data bursts according to delay time and blocking rate. A switching unit switches the data bursts to an output port of a corresponding destination node. A first buffer delays data bursts from the control module once by a preset delay time according to output resource availability and sends them to the output port when the data bursts are sensitive to delay time. A second buffer circulates and delays the sorted and confirmed data bursts up to a preset limit according to output resource availability and then sends the data bursts to the output port when the data bursts are insensitive to delay time.