It is provided a storage system for storing data requested by a host computer to be written, the storage system comprising: at least one processor, a cache memory and a cache controller. The cache memory includes a first memory which can be accessed by way of either access that can specify an access range by a line or access that continuously performs a read and a write. The cache controller includes a second memory which has a higher flexibility than the first memory in specifying an access range. The cache controller determines an address of an access destination upon reception of a request for an access to the cache memory from the at least one processor, and switches a request for an access to a specific address into an access to a corresponding address in the second memory.