A phase change memory device includes a phase change memory unit and a heat sink. The phase change memory unit includes a phase change material layer pattern, a lower electrode beneath the phase change material layer pattern configured to heat the phase change material layer pattern, and an upper electrode on the phase change material layer pattern. The heat sink configured to absorb heat from the phase change memory unit. The heat sink has a top surface lower than a top surface of the upper electrode and is spaced apart from the phase change memory unit.