An output driver of a semiconductor memory device is capable of controlling falling and rising edges of an output data. The output driver prevents the first output data form being relatively deteriorated compared with other output data in case that the output data are terminated centering around a predetermined voltage level. The output driver includes a pull-up driver for pull-up driving an output terminal in response to a pull-up control signal, a pull-down driver for pull-down driving the output terminal in response to a pull-down control signal, a first acceleration driver for accelerating the pull-up control signal, and a second acceleration driver for accelerating the pull-down control signal, wherein the first and second acceleration drivers are activated when a first data is outputted.