A vertical type semiconductor device includes a substrate that has a plurality of trenches, a support pattern that fills the plurality of trenches and protrudes from a top surface of the substrate, a semiconductor layer disposed on the substrate that fills a space between the support patterns, a stacked structure disposed on the support pattern and the semiconductor layer that includes a plurality of insulation layers and a plurality of first conducive patterns that are alternately and repeatedly stacked, and a plurality of channel structures that penetrate through the structure and the semiconductor layer and that extend into the support pattern. Each channel structure includes a channel layer. At least a portion of the channel layer makes contact with the semiconductor layer.