A semiconductor memory device includes a cell matrix having a number of cells, a multiplicity of column decoders for selectively activating the cells in response to code signals containing column address information for the cells, wherein each column decoder contains a pre-driving unit for providing a state output signal transiting between a power supply voltage and a source voltage in response to the code signals and a driving unit for outputting a column selection signal to activate a corresponding cell in response to the state output signal, wherein the pre-driving unit and the driving unit include at least one PMOS transistor and at least one NMOS transistor receiving a pumping voltage and a back-bias voltage, respectively, through their bulk, the pumping voltage having a voltage level higher than that of the power supply voltage and the back-bias voltage having a voltage level lower than that of a ground voltage.