A semiconductor memory device of the invention comprises a plurality of bit lines formed by implanting a second conductive-type impurity in a first conductive-type semiconductor substrate; a thick insulating film on the bit lines; a thin insulating film between the neighboring bit lines; and a plurality of word lines formed on the thick and thin insulating films so as to cross the bit lines, wherein each of the word lines includes a plurality of first conductors and a second conductor which electrically connects the first conductors in series, the respective first conductors are formed on the thin insulating film, the top face of the thickest portion of the thick insulating film is higher than the top face of the first conductors, and the film thickness of the thick insulating film is made thinner toward the end.