A memory device and a method for fabricating the memory device are provided. The memory device includes a substrate having an upper surface; a stack disposed on the substrate, wherein the stack includes a first insulating layer, a first conductive layer, a second insulating layer, a second conductive layer, and a third insulating layer sequentially stacked on the upper surface of the substrate along a first direction; a channel layer penetrating the stack along the first direction, wherein the channel layer has a ring shape along a cross section view in a plane perpendicular to the first direction; and a memory layer disposed between the channel layer and the second conductive layer.