A quantum semiconductor memory device includes a quantum structure formed on a substrate, wherein the quantum structure includes a plurality of self-organized quantum dots forming a strained heteroepitaxial system with respect to the substrate and an accumulation layer formed adjacent to the self-organized quantum dots, and wherein the self-organized quantum dots are formed of a semiconductor crystal having a composition set such that quantum levels of the self-organized quantum dots are located higher than a conduction band of the accumulation layer.