Disclosed is a word line driver circuit and a driving method thereof. An input to the circuit has a ground voltage level during a non-selected operating mode and, as the output signal of a word line decoding circuit, is applied at a power source voltage level during a selected operating mode. The output of the circuit has a ground voltage level during the non-selected operating mode and applies a higher voltage than the power source voltage to a word line connected to a memory cell during the selected operating mode. Optionally, a capacitor boosts the output voltage during the selected operating mode.