A manufacturing method of a semiconductor storage device includes forming a plurality of bit line structures on a semiconductor substrate and forming a plurality of storage node contacts disposed between the bit line structures. The method of forming the storage node contacts includes forming a plurality of conductive patterns on the semiconductor substrate followed by performing an etching back process to the conductive patterns for decreasing a thickness of the conductive patterns. The manufacturing method further includes forming a plurality of isolation patterns between the conductive patterns, wherein the isolation patterns are formed after forming the plurality of conductive patterns and before the etching back process. According to the present invention, the storage node contacts are formed by first forming the conductive patterns and then forming the isolation patterns between the conductive patterns, so as to simplify manufacturing process and increase process yield.