A semiconductor device includes at least one first conductive layer stacked on a substrate where a cell region and a contact region are defined; at least one first slit passing through the first conductive layer, second conductive layers stacked on the first conductive layer; a second slit passing through the first and second conductive layers and connected with one side of the first slit, and a third slit passing through the first and second conductive layers and connected with the other side of the first slit.