According to an embodiment, a storage device includes a plurality of memory nodes and a control unit. Each of the memory nodes includes a storage unit including a plurality of storage areas having a predetermined size. The memory nodes are connected to each other in two or more different directions. The memory nodes constitute two or more groups each including two or more memory nodes. The control unit is configured to sequentially allocate data writing destinations in the storage units to the storage areas respectively included in the different groups.