A memory device includes a substrate, a laminated structure and a memory string. The laminated structure is disposed on the substrate. The laminated structure includes a plurality of insulating layers and a plurality of conductive layers alternately stacked along a first direction. The memory string is accommodated in the laminated structure along the first direction. The memory string includes a memory layer and a channel layer, and the memory layer is disposed between the laminated structure and the channel layer. At least a portion of the memory layer and the insulating layers are overlapped along the first direction.