A first level metal interconnection line in a layer below a third level metal interconnection line serving as a main word line MWL is used as a shunting interconnection line and electrically connected to a first level polysilicon interconnection line constituting a sub word line SWL at prescribed intervals. By applying a hierarchical word line structure and a word line shunting structure both, a word line is driven into a selected state at high speed without increasing an array occupancy area and manufacturing steps.