According to one embodiment, a memory system including a key-value store containing key-value data as a pair of a key and a value corresponding to the key, includes a first memory, a control circuit and a second memory. The first memory is configured to contain a data area for storing data, and a table area containing the key-value data. The control circuit is configured to perform write and read to the first memory by addressing, and execute a request based on the key-value store. The second memory is configured to store the key-value data in accordance with an instruction from the control circuit. The control circuit performs a set operation by using the key-value data stored in the first memory, and the key-value data stored in the second memory.