To provide an electronic device for efficiently reducing power consumption by carrying out defragmentation without influencing other processing.

The electronic device having a normal mode operated with first electric power and a power-saving mode operated with second electric power lower than the first electric power, includes a processor including a CPU; a memory device having a volatile memory storing a memory management table indicating the corresponding relation between physical addresses and logical addresses, and a defragmentation executing part for executing defragmentation; and an electric power supply device for supplying electric power to the processor and the memory device, and at least to the processor, reducing supply electric power in the power-saving mode compared with the normal mode or stopping electric power supply.