A memory system of embodiments includes a container, a first circuit board, a second circuit board, and an optical cable. The container has a hole connecting inside and outside the container. The first circuit board is disposed outside the container and has a first circuit to convert a first electric signal to an optical signal. The second circuit board is disposed inside the container and has a memory device, and a second circuit to convert the optical signal into a second electric signal and storing the second electric signal in the memory device. The optical cable transmits the optical signal from the first circuit board through the hole to the second circuit board.