Abstract: A NAND-type flash memory device is provided. The flash memory device comprises a plurality of word line patterns formed on the substrate. The total number of the word line patterns is N. The word line patterns are disposed parallel to a string selection line pattern. The word line patterns are disposed between the ground selection line pattern and the string selection line pattern in plan view, and comprises a first word line pattern, a Nth word line pattern and intermediate word line patterns. The first word line pattern is adjacent to the string selection line pattern. The Nth word line pattern is adjacent to the ground selection line pattern. The intermediate word line patterns are disposed between the first and Nth word line patterns in plan view. The first and Nth word line patterns are wider than the intermediate word line patterns.