A memory device includes: a resistive switching layer, a conductive pillar, a barrier layer, a word line, a plurality of resistive layers, and a plurality of bit lines. The resistive switching layer is shaped as a cup and has an inner surface to define an opening. The conductive pillar is disposed in the opening. The barrier layer is disposed between the resistive switching layer and the conductive pillar. The word line is electrically connected to the conductive pillar. The resistive layers are respectively distributed on an outer surface of the resistive switching layer. The bit lines are electrically connected to the resistive layers, respectively.