A storage device includes a non-volatile memory and a control circuit that reads data in units of cluster, and erase data in units of logical block which includes a plurality of clusters. Data in each cluster includes a first error correction code and each cluster is arranged in at least one error correction group, each including clusters and a second error correction code. The control circuit performs a refresh operation in units of cluster such that refresh target data in a cluster of a first logical block is moved to a cluster of a second logical block. A first error correction group related to the refresh target data includes the cluster of the first logical block before the moving, and the first error correction group related to the refresh target data includes a cluster of the first logical block and a cluster of the second logical block after the moving.