A semiconductor memory device includes a main word line shared by a plurality of mats. Each of the mats includes a plurality of sub word lines. A decoding unit is configured to decode a row address bit and output a word line driving signal. A plurality of sub word line driving units are each configured to activate one of the sub word lines according to the word line driving signal. In the semiconductor memory device each neighboring sub word line driving units is connected to a different main word line to remove parasitic coupling capacitance.