To reduce the voltage required to cause a phase transition from an amorphous phase to a crystalline phase, a phase-change memory device (1) comprises: a first electrode (6); a second electrode (8); and a memory layer (14) provided between the first (6) and second (8) electrodes, wherein the memory layer (14) includes at least a first layer (10) formed from a phase-change material which is stable in either the amorphous phase or the crystalline phase at room temperature, and a second layer (12) formed from a resistive material, and wherein the resistance value of the second layer (12) is smaller than the resistance value of the first layer (10) in the amorphous phase, but is larger than the resistance value of the first layer (10) in the crystalline phase.