A semiconductor device and a manufacturing method of the semiconductor device are provided. The semiconductor device includes a stacked structure including a plurality of conductive patterns and a plurality of insulating patterns alternately stacked on each other, a cell plug passing through the stacked structure, a select plug coupled to the cell plug, and a select pattern surrounding the select plug, wherein the select pattern includes a first conductive portion and a second conductive portion covering a sidewall and a top surface of the first conductive portion, and wherein the conductive patterns, the first conductive portion, and the second conductive portion include different materials.