Provided is a memory device, including a stacked structure, a pillar, a first stop layer, and a contact plug. The stacked structure includes a plurality of conductive layers. The pillar penetrates the plurality of series-connected memory cells. The plurality of series-connected memory cells are located in a layout pattern of pillar locations at cross-points between the pillar and the conductive layers. The first stop layer covers the stacked structure and a portion of a top surface of the pillar. The contact plug passes through the first stop layer, extending into the pillar, and is electrically connected to the plurality of series-connected memory cells. The contact is landed on the contact plug, and is electrically connected to a portion of the pillar through the contact plug.