A memory system includes a memory device including first storage elements which store data, a temperature sensor which measures a temperature of the memory device, and a controller including a processor which acquires a current temperature from the temperature sensor as a first temperature, acquires a temperature when the data is written into the first storage element, from the memory device as a second temperature, determines whether a difference between the first temperature and the second temperature exceeds a predetermined temperature difference, and when the difference exceeds the predetermined temperature difference, instructs the memory device to rewrite the data written in the first storage element. The memory device includes a sequencer which determines a voltage for the rewrite, based on the difference and a voltage when the data is written into the first storage element.